Add m-esr52 at 52.6.0

1 files changed, 4168 insertions, 0 deletions

diff --git a/dom/xhr/XMLHttpRequestMainThread.cpp b/dom/xhr/XMLHttpRequestMainThread.cpp
new file mode 100644
index 000000000..a47a01aa0
--- /dev/null
+++ b/dom/xhr/XMLHttpRequestMainThread.cpp
@@ -0,0 +1,4168 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "XMLHttpRequestMainThread.h"
+
+#include <algorithm>
+#ifndef XP_WIN
+#include <unistd.h>
+#endif
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/dom/BlobSet.h"
+#include "mozilla/dom/DOMString.h"
+#include "mozilla/dom/File.h"
+#include "mozilla/dom/FetchUtil.h"
+#include "mozilla/dom/FormData.h"
+#include "mozilla/dom/MutableBlobStorage.h"
+#include "mozilla/dom/XMLDocument.h"
+#include "mozilla/dom/URLSearchParams.h"
+#include "mozilla/EventDispatcher.h"
+#include "mozilla/EventListenerManager.h"
+#include "mozilla/LoadInfo.h"
+#include "mozilla/LoadContext.h"
+#include "mozilla/MemoryReporting.h"
+#include "nsIDOMDocument.h"
+#include "mozilla/dom/ProgressEvent.h"
+#include "nsIJARChannel.h"
+#include "nsIJARURI.h"
+#include "nsLayoutCID.h"
+#include "nsReadableUtils.h"
+
+#include "nsIURI.h"
+#include "nsILoadGroup.h"
+#include "nsNetUtil.h"
+#include "nsStringStream.h"
+#include "nsIAuthPrompt.h"
+#include "nsIAuthPrompt2.h"
+#include "nsIOutputStream.h"
+#include "nsISupportsPrimitives.h"
+#include "nsIInterfaceRequestorUtils.h"
+#include "nsStreamUtils.h"
+#include "nsThreadUtils.h"
+#include "nsIUploadChannel.h"
+#include "nsIUploadChannel2.h"
+#include "nsIDOMSerializer.h"
+#include "nsXPCOM.h"
+#include "nsIDOMEventListener.h"
+#include "nsIScriptSecurityManager.h"
+#include "nsIVariant.h"
+#include "nsVariant.h"
+#include "nsIScriptError.h"
+#include "nsIStreamConverterService.h"
+#include "nsICachingChannel.h"
+#include "nsContentUtils.h"
+#include "nsCycleCollectionParticipant.h"
+#include "nsError.h"
+#include "nsIHTMLDocument.h"
+#include "nsIStorageStream.h"
+#include "nsIPromptFactory.h"
+#include "nsIWindowWatcher.h"
+#include "nsIConsoleService.h"
+#include "nsIContentSecurityPolicy.h"
+#include "nsAsyncRedirectVerifyHelper.h"
+#include "nsStringBuffer.h"
+#include "nsIFileChannel.h"
+#include "mozilla/Telemetry.h"
+#include "jsfriendapi.h"
+#include "GeckoProfiler.h"
+#include "mozilla/dom/EncodingUtils.h"
+#include "nsIUnicodeDecoder.h"
+#include "mozilla/dom/XMLHttpRequestBinding.h"
+#include "mozilla/Attributes.h"
+#include "MultipartBlobImpl.h"
+#include "nsIPermissionManager.h"
+#include "nsMimeTypes.h"
+#include "nsIHttpChannelInternal.h"
+#include "nsIClassOfService.h"
+#include "nsCharSeparatedTokenizer.h"
+#include "nsStreamListenerWrapper.h"
+#include "xpcjsid.h"
+#include "nsITimedChannel.h"
+#include "nsWrapperCacheInlines.h"
+#include "nsZipArchive.h"
+#include "mozilla/Preferences.h"
+#include "private/pprio.h"
+#include "XMLHttpRequestUpload.h"
+
+using namespace mozilla::net;
+
+namespace mozilla {
+namespace dom {
+
+// Maximum size that we'll grow an ArrayBuffer instead of doubling,
+// once doubling reaches this threshold
+const uint32_t XML_HTTP_REQUEST_ARRAYBUFFER_MAX_GROWTH = 32*1024*1024;
+// start at 32k to avoid lots of doubling right at the start
+const uint32_t XML_HTTP_REQUEST_ARRAYBUFFER_MIN_SIZE = 32*1024;
+// the maximum Content-Length that we'll preallocate.  1GB.  Must fit
+// in an int32_t!
+const int32_t XML_HTTP_REQUEST_MAX_CONTENT_LENGTH_PREALLOCATE = 1*1024*1024*1024LL;
+
+namespace {
+  const nsLiteralString ProgressEventTypeStrings[] = {
+    NS_LITERAL_STRING("loadstart"),
+    NS_LITERAL_STRING("progress"),
+    NS_LITERAL_STRING("error"),
+    NS_LITERAL_STRING("abort"),
+    NS_LITERAL_STRING("timeout"),
+    NS_LITERAL_STRING("load"),
+    NS_LITERAL_STRING("loadend")
+  };
+  static_assert(MOZ_ARRAY_LENGTH(ProgressEventTypeStrings) ==
+                  size_t(XMLHttpRequestMainThread::ProgressEventType::ENUM_MAX),
+                "Mismatched lengths for ProgressEventTypeStrings and ProgressEventType enums");
+
+  const nsString kLiteralString_readystatechange = NS_LITERAL_STRING("readystatechange");
+  const nsString kLiteralString_xmlhttprequest = NS_LITERAL_STRING("xmlhttprequest");
+  const nsString kLiteralString_DOMContentLoaded = NS_LITERAL_STRING("DOMContentLoaded");
+}
+
+// CIDs
+#define NS_BADCERTHANDLER_CONTRACTID \
+  "@mozilla.org/content/xmlhttprequest-bad-cert-handler;1"
+
+#define NS_PROGRESS_EVENT_INTERVAL 50
+#define MAX_SYNC_TIMEOUT_WHEN_UNLOADING 10000 /* 10 secs */
+
+NS_IMPL_ISUPPORTS(nsXHRParseEndListener, nsIDOMEventListener)
+
+class nsResumeTimeoutsEvent : public Runnable
+{
+public:
+  explicit nsResumeTimeoutsEvent(nsPIDOMWindowInner* aWindow) : mWindow(aWindow) {}
+
+  NS_IMETHOD Run() override
+  {
+    mWindow->Resume();
+    return NS_OK;
+  }
+
+private:
+  nsCOMPtr<nsPIDOMWindowInner> mWindow;
+};
+
+
+// This helper function adds the given load flags to the request's existing
+// load flags.
+static void AddLoadFlags(nsIRequest *request, nsLoadFlags newFlags)
+{
+  nsLoadFlags flags;
+  request->GetLoadFlags(&flags);
+  flags |= newFlags;
+  request->SetLoadFlags(flags);
+}
+
+/////////////////////////////////////////////
+//
+//
+/////////////////////////////////////////////
+
+bool
+XMLHttpRequestMainThread::sDontWarnAboutSyncXHR = false;
+
+XMLHttpRequestMainThread::XMLHttpRequestMainThread()
+  : mResponseBodyDecodedPos(0),
+    mResponseType(XMLHttpRequestResponseType::_empty),
+    mRequestObserver(nullptr),
+    mState(State::unsent),
+    mFlagSynchronous(false), mFlagAborted(false), mFlagParseBody(false),
+    mFlagSyncLooping(false), mFlagBackgroundRequest(false),
+    mFlagHadUploadListenersOnSend(false), mFlagACwithCredentials(false),
+    mFlagTimedOut(false), mFlagDeleted(false), mFlagSend(false),
+    mUploadTransferred(0), mUploadTotal(0), mUploadComplete(true),
+    mProgressSinceLastProgressEvent(false),
+    mRequestSentTime(0), mTimeoutMilliseconds(0),
+    mErrorLoad(false), mErrorParsingXML(false),
+    mWaitingForOnStopRequest(false),
+    mProgressTimerIsActive(false),
+    mIsHtml(false),
+    mWarnAboutSyncHtml(false),
+    mLoadTotal(-1),
+    mIsSystem(false),
+    mIsAnon(false),
+    mFirstStartRequestSeen(false),
+    mInLoadProgressEvent(false),
+    mResultJSON(JS::UndefinedValue()),
+    mResultArrayBuffer(nullptr),
+    mIsMappedArrayBuffer(false),
+    mXPCOMifier(nullptr)
+{
+  mozilla::HoldJSObjects(this);
+}
+
+XMLHttpRequestMainThread::~XMLHttpRequestMainThread()
+{
+  mFlagDeleted = true;
+
+  if ((mState == State::opened && mFlagSend) ||
+      mState == State::loading) {
+    Abort();
+  }
+
+  MOZ_ASSERT(!mFlagSyncLooping, "we rather crash than hang");
+  mFlagSyncLooping = false;
+
+  mResultJSON.setUndefined();
+  mResultArrayBuffer = nullptr;
+  mozilla::DropJSObjects(this);
+}
+
+/**
+ * This Init method is called from the factory constructor.
+ */
+nsresult
+XMLHttpRequestMainThread::Init()
+{
+  nsIScriptSecurityManager* secMan = nsContentUtils::GetSecurityManager();
+  nsCOMPtr<nsIPrincipal> subjectPrincipal;
+  if (secMan) {
+    secMan->GetSystemPrincipal(getter_AddRefs(subjectPrincipal));
+  }
+  NS_ENSURE_STATE(subjectPrincipal);
+
+  // Instead of grabbing some random global from the context stack,
+  // let's use the default one (junk scope) for now.
+  // We should move away from this Init...
+  Construct(subjectPrincipal, xpc::NativeGlobal(xpc::PrivilegedJunkScope()));
+  return NS_OK;
+}
+
+/**
+ * This Init method should only be called by C++ consumers.
+ */
+NS_IMETHODIMP
+XMLHttpRequestMainThread::Init(nsIPrincipal* aPrincipal,
+                               nsIGlobalObject* aGlobalObject,
+                               nsIURI* aBaseURI,
+                               nsILoadGroup* aLoadGroup)
+{
+  NS_ENSURE_ARG_POINTER(aPrincipal);
+  Construct(aPrincipal, aGlobalObject, aBaseURI, aLoadGroup);
+  return NS_OK;
+}
+
+void
+XMLHttpRequestMainThread::InitParameters(bool aAnon, bool aSystem)
+{
+  if (!aAnon && !aSystem) {
+    return;
+  }
+
+  // Check for permissions.
+  // Chrome is always allowed access, so do the permission check only
+  // for non-chrome pages.
+  if (!IsSystemXHR() && aSystem) {
+    nsIGlobalObject* global = GetOwnerGlobal();
+    if (NS_WARN_IF(!global)) {
+      SetParameters(aAnon, false);
+      return;
+    }
+
+    nsIPrincipal* principal = global->PrincipalOrNull();
+    if (NS_WARN_IF(!principal)) {
+      SetParameters(aAnon, false);
+      return;
+    }
+
+    nsCOMPtr<nsIPermissionManager> permMgr =
+      services::GetPermissionManager();
+    if (NS_WARN_IF(!permMgr)) {
+      SetParameters(aAnon, false);
+      return;
+    }
+
+    uint32_t permission;
+    nsresult rv =
+      permMgr->TestPermissionFromPrincipal(principal, "systemXHR", &permission);
+    if (NS_FAILED(rv) || permission != nsIPermissionManager::ALLOW_ACTION) {
+      SetParameters(aAnon, false);
+      return;
+    }
+  }
+
+  SetParameters(aAnon, aSystem);
+}
+
+void
+XMLHttpRequestMainThread::ResetResponse()
+{
+  mResponseXML = nullptr;
+  mResponseBody.Truncate();
+  TruncateResponseText();
+  mResponseBlob = nullptr;
+  mDOMBlob = nullptr;
+  mBlobStorage = nullptr;
+  mBlobSet = nullptr;
+  mResultArrayBuffer = nullptr;
+  mArrayBufferBuilder.reset();
+  mResultJSON.setUndefined();
+  mDataAvailable = 0;
+  mLoadTransferred = 0;
+  mResponseBodyDecodedPos = 0;
+}
+
+void
+XMLHttpRequestMainThread::SetRequestObserver(nsIRequestObserver* aObserver)
+{
+  mRequestObserver = aObserver;
+}
+
+NS_IMPL_CYCLE_COLLECTION_CLASS(XMLHttpRequestMainThread)
+
+NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_BEGIN(XMLHttpRequestMainThread)
+  bool isBlack = tmp->IsBlack();
+  if (isBlack || tmp->mWaitingForOnStopRequest) {
+    if (tmp->mListenerManager) {
+      tmp->mListenerManager->MarkForCC();
+    }
+    if (!isBlack && tmp->PreservingWrapper()) {
+      // This marks the wrapper black.
+      tmp->GetWrapper();
+    }
+    return true;
+  }
+NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_END
+
+NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_IN_CC_BEGIN(XMLHttpRequestMainThread)
+  return tmp->
+    IsBlackAndDoesNotNeedTracing(static_cast<DOMEventTargetHelper*>(tmp));
+NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_IN_CC_END
+
+NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_BEGIN(XMLHttpRequestMainThread)
+  return tmp->IsBlack();
+NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(XMLHttpRequestMainThread,
+                                                  XMLHttpRequestEventTarget)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mContext)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mChannel)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mResponseXML)
+
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mXMLParserStreamListener)
+
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mResponseBlob)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDOMBlob)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mNotificationCallbacks)
+
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mChannelEventSink)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mProgressEventSink)
+
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mUpload)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(XMLHttpRequestMainThread,
+                                                XMLHttpRequestEventTarget)
+  tmp->mResultArrayBuffer = nullptr;
+  tmp->mArrayBufferBuilder.reset();
+  tmp->mResultJSON.setUndefined();
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mContext)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mChannel)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mResponseXML)
+
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mXMLParserStreamListener)
+
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mResponseBlob)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mDOMBlob)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mNotificationCallbacks)
+
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mChannelEventSink)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mProgressEventSink)
+
+  NS_IMPL_CYCLE_COLLECTION_UNLINK(mUpload)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(XMLHttpRequestMainThread,
+                                               XMLHttpRequestEventTarget)
+  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mResultArrayBuffer)
+  NS_IMPL_CYCLE_COLLECTION_TRACE_JS_MEMBER_CALLBACK(mResultJSON)
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
+// QueryInterface implementation for XMLHttpRequestMainThread
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(XMLHttpRequestMainThread)
+  NS_INTERFACE_MAP_ENTRY(nsIXMLHttpRequest)
+  NS_INTERFACE_MAP_ENTRY(nsIJSXMLHttpRequest)
+  NS_INTERFACE_MAP_ENTRY(nsIRequestObserver)
+  NS_INTERFACE_MAP_ENTRY(nsIStreamListener)
+  NS_INTERFACE_MAP_ENTRY(nsIChannelEventSink)
+  NS_INTERFACE_MAP_ENTRY(nsIProgressEventSink)
+  NS_INTERFACE_MAP_ENTRY(nsIInterfaceRequestor)
+  NS_INTERFACE_MAP_ENTRY(nsISupportsWeakReference)
+  NS_INTERFACE_MAP_ENTRY(nsITimerCallback)
+  NS_INTERFACE_MAP_ENTRY(nsISizeOfEventTarget)
+NS_INTERFACE_MAP_END_INHERITING(XMLHttpRequestEventTarget)
+
+NS_IMPL_ADDREF_INHERITED(XMLHttpRequestMainThread, XMLHttpRequestEventTarget)
+NS_IMPL_RELEASE_INHERITED(XMLHttpRequestMainThread, XMLHttpRequestEventTarget)
+
+NS_IMPL_EVENT_HANDLER(XMLHttpRequestMainThread, readystatechange)
+
+void
+XMLHttpRequestMainThread::DisconnectFromOwner()
+{
+  XMLHttpRequestEventTarget::DisconnectFromOwner();
+  Abort();
+}
+
+size_t
+XMLHttpRequestMainThread::SizeOfEventTargetIncludingThis(
+  MallocSizeOf aMallocSizeOf) const
+{
+  size_t n = aMallocSizeOf(this);
+  n += mResponseBody.SizeOfExcludingThisIfUnshared(aMallocSizeOf);
+
+  // Why is this safe?  Because no-one else will report this string.  The
+  // other possible sharers of this string are as follows.
+  //
+  // - The JS engine could hold copies if the JS code holds references, e.g.
+  //   |var text = XHR.responseText|.  However, those references will be via JS
+  //   external strings, for which the JS memory reporter does *not* report the
+  //   chars.
+  //
+  // - Binary extensions, but they're *extremely* unlikely to do any memory
+  //   reporting.
+  //
+  n += mResponseText.SizeOfThis(aMallocSizeOf);
+
+  return n;
+
+  // Measurement of the following members may be added later if DMD finds it is
+  // worthwhile:
+  // - lots
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetChannel(nsIChannel **aChannel)
+{
+  NS_ENSURE_ARG_POINTER(aChannel);
+  NS_IF_ADDREF(*aChannel = mChannel);
+
+  return NS_OK;
+}
+
+static void LogMessage(const char* aWarning, nsPIDOMWindowInner* aWindow,
+                       const char16_t** aParams=nullptr, uint32_t aParamCount=0)
+{
+  nsCOMPtr<nsIDocument> doc;
+  if (aWindow) {
+    doc = aWindow->GetExtantDoc();
+  }
+  nsContentUtils::ReportToConsole(nsIScriptError::warningFlag,
+                                  NS_LITERAL_CSTRING("DOM"), doc,
+                                  nsContentUtils::eDOM_PROPERTIES,
+                                  aWarning, aParams, aParamCount);
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetResponseXML(nsIDOMDocument **aResponseXML)
+{
+  ErrorResult rv;
+  nsIDocument* responseXML = GetResponseXML(rv);
+  if (rv.Failed()) {
+    return rv.StealNSResult();
+  }
+
+  if (!responseXML) {
+    *aResponseXML = nullptr;
+    return NS_OK;
+  }
+
+  return CallQueryInterface(responseXML, aResponseXML);
+}
+
+nsIDocument*
+XMLHttpRequestMainThread::GetResponseXML(ErrorResult& aRv)
+{
+  if (mResponseType != XMLHttpRequestResponseType::_empty &&
+      mResponseType != XMLHttpRequestResponseType::Document) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_XHR_HAS_WRONG_RESPONSETYPE_FOR_RESPONSEXML);
+    return nullptr;
+  }
+  if (mWarnAboutSyncHtml) {
+    mWarnAboutSyncHtml = false;
+    LogMessage("HTMLSyncXHRWarning", GetOwner());
+  }
+  if (mState != State::done) {
+    return nullptr;
+  }
+  return mResponseXML;
+}
+
+/*
+ * This piece copied from XMLDocument, we try to get the charset
+ * from HTTP headers.
+ */
+nsresult
+XMLHttpRequestMainThread::DetectCharset()
+{
+  mResponseCharset.Truncate();
+  mDecoder = nullptr;
+
+  if (mResponseType != XMLHttpRequestResponseType::_empty &&
+      mResponseType != XMLHttpRequestResponseType::Text &&
+      mResponseType != XMLHttpRequestResponseType::Json &&
+      mResponseType != XMLHttpRequestResponseType::Moz_chunked_text) {
+    return NS_OK;
+  }
+
+  nsAutoCString charsetVal;
+  bool ok = mChannel &&
+            NS_SUCCEEDED(mChannel->GetContentCharset(charsetVal)) &&
+            EncodingUtils::FindEncodingForLabel(charsetVal, mResponseCharset);
+  if (!ok || mResponseCharset.IsEmpty()) {
+    // MS documentation states UTF-8 is default for responseText
+    mResponseCharset.AssignLiteral("UTF-8");
+  }
+
+  if (mResponseType == XMLHttpRequestResponseType::Json &&
+      !mResponseCharset.EqualsLiteral("UTF-8")) {
+    // The XHR spec says only UTF-8 is supported for responseType == "json"
+    LogMessage("JSONCharsetWarning", GetOwner());
+    mResponseCharset.AssignLiteral("UTF-8");
+  }
+
+  mDecoder = EncodingUtils::DecoderForEncoding(mResponseCharset);
+
+  return NS_OK;
+}
+
+nsresult
+XMLHttpRequestMainThread::AppendToResponseText(const char * aSrcBuffer,
+                                               uint32_t aSrcBufferLen)
+{
+  NS_ENSURE_STATE(mDecoder);
+
+  int32_t destBufferLen;
+  nsresult rv = mDecoder->GetMaxLength(aSrcBuffer, aSrcBufferLen,
+                                       &destBufferLen);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  CheckedInt32 size = mResponseText.Length();
+  size += destBufferLen;
+  if (!size.isValid()) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  XMLHttpRequestStringWriterHelper helper(mResponseText);
+
+  if (!helper.AddCapacity(destBufferLen)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  // This code here is basically a copy of a similar thing in
+  // nsScanner::Append(const char* aBuffer, uint32_t aLen).
+  int32_t srclen = (int32_t)aSrcBufferLen;
+  int32_t destlen = (int32_t)destBufferLen;
+  rv = mDecoder->Convert(aSrcBuffer,
+                         &srclen,
+                         helper.EndOfExistingData(),
+                         &destlen);
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+  MOZ_ASSERT(destlen <= destBufferLen);
+
+  helper.AddLength(destlen);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetResponseText(nsAString& aResponseText)
+{
+  ErrorResult rv;
+  DOMString str;
+  GetResponseText(str, rv);
+  if (NS_WARN_IF(rv.Failed())) {
+    return rv.StealNSResult();
+  }
+
+  str.ToString(aResponseText);
+  return NS_OK;
+}
+
+void
+XMLHttpRequestMainThread::GetResponseText(DOMString& aResponseText,
+                                          ErrorResult& aRv)
+{
+  XMLHttpRequestStringSnapshot snapshot;
+  GetResponseText(snapshot, aRv);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  if (!snapshot.GetAsString(aResponseText)) {
+    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+    return;
+  }
+}
+
+void
+XMLHttpRequestMainThread::GetResponseText(XMLHttpRequestStringSnapshot& aSnapshot,
+                                          ErrorResult& aRv)
+{
+  aSnapshot.Reset();
+
+  if (mResponseType != XMLHttpRequestResponseType::_empty &&
+      mResponseType != XMLHttpRequestResponseType::Text &&
+      mResponseType != XMLHttpRequestResponseType::Moz_chunked_text) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_XHR_HAS_WRONG_RESPONSETYPE_FOR_RESPONSETEXT);
+    return;
+  }
+
+  if (mResponseType == XMLHttpRequestResponseType::Moz_chunked_text &&
+      !mInLoadProgressEvent) {
+    aSnapshot.SetVoid();
+    return;
+  }
+
+  if (mState != State::loading && mState != State::done) {
+    return;
+  }
+
+  // We only decode text lazily if we're also parsing to a doc.
+  // Also, if we've decoded all current data already, then no need to decode
+  // more.
+  if ((!mResponseXML && !mErrorParsingXML) ||
+      mResponseBodyDecodedPos == mResponseBody.Length()) {
+    mResponseText.CreateSnapshot(aSnapshot);
+    return;
+  }
+
+  MatchCharsetAndDecoderToResponseDocument();
+
+  NS_ASSERTION(mResponseBodyDecodedPos < mResponseBody.Length(),
+               "Unexpected mResponseBodyDecodedPos");
+  aRv = AppendToResponseText(mResponseBody.get() + mResponseBodyDecodedPos,
+                             mResponseBody.Length() - mResponseBodyDecodedPos);
+  if (aRv.Failed()) {
+    return;
+  }
+
+  mResponseBodyDecodedPos = mResponseBody.Length();
+
+  if (mState == State::done) {
+    // Free memory buffer which we no longer need
+    mResponseBody.Truncate();
+    mResponseBodyDecodedPos = 0;
+  }
+
+  mResponseText.CreateSnapshot(aSnapshot);
+}
+
+nsresult
+XMLHttpRequestMainThread::CreateResponseParsedJSON(JSContext* aCx)
+{
+  if (!aCx) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsAutoString string;
+  if (!mResponseText.GetAsString(string)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  // The Unicode converter has already zapped the BOM if there was one
+  JS::Rooted<JS::Value> value(aCx);
+  if (!JS_ParseJSON(aCx, string.BeginReading(), string.Length(), &value)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mResultJSON = value;
+  return NS_OK;
+}
+
+void
+XMLHttpRequestMainThread::CreatePartialBlob(ErrorResult& aRv)
+{
+  if (mDOMBlob) {
+    // Use progress info to determine whether load is complete, but use
+    // mDataAvailable to ensure a slice is created based on the uncompressed
+    // data count.
+    if (mState == State::done) {
+      mResponseBlob = mDOMBlob;
+    } else {
+      mResponseBlob = mDOMBlob->CreateSlice(0, mDataAvailable,
+                                            EmptyString(), aRv);
+    }
+    return;
+  }
+
+  // mBlobSet can be null if the request has been canceled
+  if (!mBlobSet) {
+    return;
+  }
+
+  nsAutoCString contentType;
+  if (mState == State::done) {
+    mChannel->GetContentType(contentType);
+  }
+
+  nsTArray<RefPtr<BlobImpl>> subImpls(mBlobSet->GetBlobImpls());
+  RefPtr<BlobImpl> blobImpl =
+    MultipartBlobImpl::Create(Move(subImpls),
+                              NS_ConvertASCIItoUTF16(contentType),
+                              aRv);
+  if (NS_WARN_IF(aRv.Failed())) {
+    return;
+  }
+
+  mResponseBlob = Blob::Create(GetOwner(), blobImpl);
+}
+
+NS_IMETHODIMP XMLHttpRequestMainThread::GetResponseType(nsAString& aResponseType)
+{
+  MOZ_ASSERT(mResponseType < XMLHttpRequestResponseType::EndGuard_);
+  const EnumEntry& entry =
+    XMLHttpRequestResponseTypeValues::strings[static_cast<uint32_t>(mResponseType)];
+  aResponseType.AssignASCII(entry.value, entry.length);
+  return NS_OK;
+}
+
+NS_IMETHODIMP XMLHttpRequestMainThread::SetResponseType(const nsAString& aResponseType)
+{
+  uint32_t i = 0;
+  for (const EnumEntry* entry = XMLHttpRequestResponseTypeValues::strings;
+       entry->value; ++entry, ++i) {
+    if (aResponseType.EqualsASCII(entry->value, entry->length)) {
+      ErrorResult rv;
+      SetResponseType(static_cast<XMLHttpRequestResponseType>(i), rv);
+      return rv.StealNSResult();
+    }
+  }
+
+  return NS_OK;
+}
+
+void
+XMLHttpRequestMainThread::SetResponseType(XMLHttpRequestResponseType aResponseType,
+                                          ErrorResult& aRv)
+{
+  if (mState == State::loading || mState == State::done) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_XHR_MUST_NOT_BE_LOADING_OR_DONE);
+    return;
+  }
+
+  // sync request is not allowed setting responseType in window context
+  if (HasOrHasHadOwner() && mState != State::unsent && mFlagSynchronous) {
+    LogMessage("ResponseTypeSyncXHRWarning", GetOwner());
+    aRv.Throw(NS_ERROR_DOM_INVALID_ACCESS_XHR_TIMEOUT_AND_RESPONSETYPE_UNSUPPORTED_FOR_SYNC);
+    return;
+  }
+
+  if (mFlagSynchronous &&
+      (aResponseType == XMLHttpRequestResponseType::Moz_chunked_text ||
+       aResponseType == XMLHttpRequestResponseType::Moz_chunked_arraybuffer)) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_XHR_CHUNKED_RESPONSETYPES_UNSUPPORTED_FOR_SYNC);
+    return;
+  }
+
+  // We want to get rid of this moz-only types. Bug 1335365.
+  if (aResponseType == XMLHttpRequestResponseType::Moz_blob) {
+    Telemetry::Accumulate(Telemetry::MOZ_BLOB_IN_XHR, 1);
+  } else if (aResponseType == XMLHttpRequestResponseType::Moz_chunked_text) {
+    Telemetry::Accumulate(Telemetry::MOZ_CHUNKED_TEXT_IN_XHR, 1);
+  } else if (aResponseType == XMLHttpRequestResponseType::Moz_chunked_arraybuffer) {
+    Telemetry::Accumulate(Telemetry::MOZ_CHUNKED_ARRAYBUFFER_IN_XHR, 1);
+  }
+
+  // Set the responseType attribute's value to the given value.
+  mResponseType = aResponseType;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetResponse(JSContext *aCx, JS::MutableHandle<JS::Value> aResult)
+{
+  ErrorResult rv;
+  GetResponse(aCx, aResult, rv);
+  return rv.StealNSResult();
+}
+
+void
+XMLHttpRequestMainThread::GetResponse(JSContext* aCx,
+                                      JS::MutableHandle<JS::Value> aResponse,
+                                      ErrorResult& aRv)
+{
+  switch (mResponseType) {
+  case XMLHttpRequestResponseType::_empty:
+  case XMLHttpRequestResponseType::Text:
+  case XMLHttpRequestResponseType::Moz_chunked_text:
+  {
+    DOMString str;
+    GetResponseText(str, aRv);
+    if (aRv.Failed()) {
+      return;
+    }
+    if (!xpc::StringToJsval(aCx, str, aResponse)) {
+      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+    }
+    return;
+  }
+
+  case XMLHttpRequestResponseType::Arraybuffer:
+  case XMLHttpRequestResponseType::Moz_chunked_arraybuffer:
+  {
+    if (!(mResponseType == XMLHttpRequestResponseType::Arraybuffer &&
+          mState == State::done) &&
+        !(mResponseType == XMLHttpRequestResponseType::Moz_chunked_arraybuffer &&
+          mInLoadProgressEvent)) {
+      aResponse.setNull();
+      return;
+    }
+
+    if (!mResultArrayBuffer) {
+      mResultArrayBuffer = mArrayBufferBuilder.getArrayBuffer(aCx);
+      if (!mResultArrayBuffer) {
+        aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+        return;
+      }
+    }
+    aResponse.setObject(*mResultArrayBuffer);
+    return;
+  }
+  case XMLHttpRequestResponseType::Blob:
+  case XMLHttpRequestResponseType::Moz_blob:
+  {
+    if (mState != State::done) {
+      if (mResponseType != XMLHttpRequestResponseType::Moz_blob) {
+        aResponse.setNull();
+        return;
+      }
+
+      if (!mResponseBlob) {
+        CreatePartialBlob(aRv);
+      }
+    }
+
+    if (!mResponseBlob) {
+      aResponse.setNull();
+      return;
+    }
+
+    GetOrCreateDOMReflector(aCx, mResponseBlob, aResponse);
+    return;
+  }
+  case XMLHttpRequestResponseType::Document:
+  {
+    if (!mResponseXML || mState != State::done) {
+      aResponse.setNull();
+      return;
+    }
+
+    aRv = nsContentUtils::WrapNative(aCx, mResponseXML, aResponse);
+    return;
+  }
+  case XMLHttpRequestResponseType::Json:
+  {
+    if (mState != State::done) {
+      aResponse.setNull();
+      return;
+    }
+
+    if (mResultJSON.isUndefined()) {
+      aRv = CreateResponseParsedJSON(aCx);
+      TruncateResponseText();
+      if (aRv.Failed()) {
+        // Per spec, errors aren't propagated. null is returned instead.
+        aRv = NS_OK;
+        // It would be nice to log the error to the console. That's hard to
+        // do without calling window.onerror as a side effect, though.
+        JS_ClearPendingException(aCx);
+        mResultJSON.setNull();
+      }
+    }
+    aResponse.set(mResultJSON);
+    return;
+  }
+  default:
+    NS_ERROR("Should not happen");
+  }
+
+  aResponse.setNull();
+}
+
+bool
+XMLHttpRequestMainThread::IsCrossSiteCORSRequest() const
+{
+  if (!mChannel) {
+    return false;
+  }
+
+  nsCOMPtr<nsILoadInfo> loadInfo = mChannel->GetLoadInfo();
+  MOZ_ASSERT(loadInfo);
+
+  return loadInfo->GetTainting() == LoadTainting::CORS;
+}
+
+bool
+XMLHttpRequestMainThread::IsDeniedCrossSiteCORSRequest()
+{
+  if (IsCrossSiteCORSRequest()) {
+    nsresult rv;
+    mChannel->GetStatus(&rv);
+    if (NS_FAILED(rv)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void
+XMLHttpRequestMainThread::GetResponseURL(nsAString& aUrl)
+{
+  aUrl.Truncate();
+
+  uint16_t readyState = ReadyState();
+  if ((readyState == UNSENT || readyState == OPENED) || !mChannel) {
+    return;
+  }
+
+  // Make sure we don't leak responseURL information from denied cross-site
+  // requests.
+  if (IsDeniedCrossSiteCORSRequest()) {
+    return;
+  }
+
+  nsCOMPtr<nsIURI> responseUrl;
+  mChannel->GetURI(getter_AddRefs(responseUrl));
+
+  if (!responseUrl) {
+    return;
+  }
+
+  nsAutoCString temp;
+  responseUrl->GetSpecIgnoringRef(temp);
+  CopyUTF8toUTF16(temp, aUrl);
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetStatus(uint32_t *aStatus)
+{
+  ErrorResult rv;
+  *aStatus = GetStatus(rv);
+  return rv.StealNSResult();
+}
+
+uint32_t
+XMLHttpRequestMainThread::GetStatus(ErrorResult& aRv)
+{
+  // Make sure we don't leak status information from denied cross-site
+  // requests.
+  if (IsDeniedCrossSiteCORSRequest()) {
+    return 0;
+  }
+
+  uint16_t readyState = ReadyState();
+  if (readyState == UNSENT || readyState == OPENED) {
+    return 0;
+  }
+
+  if (mErrorLoad) {
+    // Let's simulate the http protocol for jar/app requests:
+    nsCOMPtr<nsIJARChannel> jarChannel = GetCurrentJARChannel();
+    if (jarChannel) {
+      nsresult status;
+      mChannel->GetStatus(&status);
+
+      if (status == NS_ERROR_FILE_NOT_FOUND) {
+        return 404; // Not Found
+      } else {
+        return 500; // Internal Error
+      }
+    }
+
+    return 0;
+  }
+
+  nsCOMPtr<nsIHttpChannel> httpChannel = GetCurrentHttpChannel();
+  if (!httpChannel) {
+    // Pretend like we got a 200 response, since our load was successful
+    return 200;
+  }
+
+  uint32_t status;
+  nsresult rv = httpChannel->GetResponseStatus(&status);
+  if (NS_FAILED(rv)) {
+    status = 0;
+  }
+
+  return status;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetStatusText(nsACString& aOut)
+{
+  ErrorResult rv;
+  GetStatusText(aOut, rv);
+  return rv.StealNSResult();
+}
+
+void
+XMLHttpRequestMainThread::GetStatusText(nsACString& aStatusText,
+                                        ErrorResult& aRv)
+{
+  // Return an empty status text on all error loads.
+  aStatusText.Truncate();
+
+  // Make sure we don't leak status information from denied cross-site
+  // requests.
+  if (IsDeniedCrossSiteCORSRequest()) {
+    return;
+  }
+
+  // Check the current XHR state to see if it is valid to obtain the statusText
+  // value.  This check is to prevent the status text for redirects from being
+  // available before all the redirects have been followed and HTTP headers have
+  // been received.
+  uint16_t readyState = ReadyState();
+  if (readyState == UNSENT || readyState == OPENED) {
+    return;
+  }
+
+  if (mErrorLoad) {
+    return;
+  }
+
+  nsCOMPtr<nsIHttpChannel> httpChannel = GetCurrentHttpChannel();
+  if (httpChannel) {
+    httpChannel->GetResponseStatusText(aStatusText);
+  } else {
+    aStatusText.AssignLiteral("OK");
+  }
+}
+
+void
+XMLHttpRequestMainThread::CloseRequest()
+{
+  mWaitingForOnStopRequest = false;
+  if (mChannel) {
+    mChannel->Cancel(NS_BINDING_ABORTED);
+  }
+  if (mTimeoutTimer) {
+    mTimeoutTimer->Cancel();
+  }
+}
+
+void
+XMLHttpRequestMainThread::CloseRequestWithError(const ProgressEventType aType)
+{
+  CloseRequest();
+
+  ResetResponse();
+
+  // If we're in the destructor, don't risk dispatching an event.
+  if (mFlagDeleted) {
+    mFlagSyncLooping = false;
+    return;
+  }
+
+  if (mState != State::unsent &&
+      !(mState == State::opened && !mFlagSend) &&
+      mState != State::done) {
+    ChangeState(State::done, true);
+
+    if (!mFlagSyncLooping) {
+      if (mUpload && !mUploadComplete) {
+        mUploadComplete = true;
+        DispatchProgressEvent(mUpload, aType, 0, -1);
+      }
+      DispatchProgressEvent(this, aType, 0, -1);
+    }
+  }
+
+  // The ChangeState call above calls onreadystatechange handlers which
+  // if they load a new url will cause XMLHttpRequestMainThread::Open to clear
+  // the abort state bit. If this occurs we're not uninitialized (bug 361773).
+  if (mFlagAborted) {
+    ChangeState(State::unsent, false);  // IE seems to do it
+  }
+
+  mFlagSyncLooping = false;
+}
+
+void
+XMLHttpRequestMainThread::Abort(ErrorResult& arv)
+{
+  mFlagAborted = true;
+  CloseRequestWithError(ProgressEventType::abort);
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::SlowAbort()
+{
+  Abort();
+  return NS_OK;
+}
+
+/*Method that checks if it is safe to expose a header value to the client.
+It is used to check what headers are exposed for CORS requests.*/
+bool
+XMLHttpRequestMainThread::IsSafeHeader(const nsACString& aHeader,
+                                       NotNull<nsIHttpChannel*> aHttpChannel) const
+{
+  // See bug #380418. Hide "Set-Cookie" headers from non-chrome scripts.
+  if (!IsSystemXHR() && nsContentUtils::IsForbiddenResponseHeader(aHeader)) {
+    NS_WARNING("blocked access to response header");
+    return false;
+  }
+  // if this is not a CORS call all headers are safe
+  if (!IsCrossSiteCORSRequest()) {
+    return true;
+  }
+  // Check for dangerous headers
+  // Make sure we don't leak header information from denied cross-site
+  // requests.
+  if (mChannel) {
+    nsresult status;
+    mChannel->GetStatus(&status);
+    if (NS_FAILED(status)) {
+      return false;
+    }
+  }
+  const char* kCrossOriginSafeHeaders[] = {
+    "cache-control", "content-language", "content-type", "expires",
+    "last-modified", "pragma"
+  };
+  for (uint32_t i = 0; i < ArrayLength(kCrossOriginSafeHeaders); ++i) {
+    if (aHeader.LowerCaseEqualsASCII(kCrossOriginSafeHeaders[i])) {
+      return true;
+    }
+  }
+  nsAutoCString headerVal;
+  // The "Access-Control-Expose-Headers" header contains a comma separated
+  // list of method names.
+  aHttpChannel->
+      GetResponseHeader(NS_LITERAL_CSTRING("Access-Control-Expose-Headers"),
+                        headerVal);
+  nsCCharSeparatedTokenizer exposeTokens(headerVal, ',');
+  bool isSafe = false;
+  while (exposeTokens.hasMoreTokens()) {
+    const nsDependentCSubstring& token = exposeTokens.nextToken();
+    if (token.IsEmpty()) {
+      continue;
+    }
+    if (!NS_IsValidHTTPToken(token)) {
+      return false;
+    }
+    if (aHeader.Equals(token, nsCaseInsensitiveCStringComparator())) {
+      isSafe = true;
+    }
+  }
+  return isSafe;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetAllResponseHeaders(nsACString& aOut)
+{
+  ErrorResult rv;
+  GetAllResponseHeaders(aOut, rv);
+  return rv.StealNSResult();
+}
+
+void
+XMLHttpRequestMainThread::GetAllResponseHeaders(nsACString& aResponseHeaders,
+                                                ErrorResult& aRv)
+{
+  aResponseHeaders.Truncate();
+
+  // If the state is UNSENT or OPENED,
+  // return the empty string and terminate these steps.
+  if (mState == State::unsent || mState == State::opened) {
+    return;
+  }
+
+  if (mErrorLoad) {
+    return;
+  }
+
+  if (nsCOMPtr<nsIHttpChannel> httpChannel = GetCurrentHttpChannel()) {
+    RefPtr<nsHeaderVisitor> visitor =
+      new nsHeaderVisitor(*this, WrapNotNull(httpChannel));
+    if (NS_SUCCEEDED(httpChannel->VisitResponseHeaders(visitor))) {
+      aResponseHeaders = visitor->Headers();
+    }
+    return;
+  }
+
+  if (!mChannel) {
+    return;
+  }
+
+  // Even non-http channels supply content type.
+  nsAutoCString value;
+  if (NS_SUCCEEDED(mChannel->GetContentType(value))) {
+    aResponseHeaders.AppendLiteral("Content-Type: ");
+    aResponseHeaders.Append(value);
+    if (NS_SUCCEEDED(mChannel->GetContentCharset(value)) && !value.IsEmpty()) {
+      aResponseHeaders.AppendLiteral(";charset=");
+      aResponseHeaders.Append(value);
+    }
+    aResponseHeaders.AppendLiteral("\r\n");
+  }
+
+  // Don't provide Content-Length for data URIs
+  nsCOMPtr<nsIURI> uri;
+  bool isDataURI;
+  if (NS_FAILED(mChannel->GetURI(getter_AddRefs(uri))) ||
+      NS_FAILED(uri->SchemeIs("data", &isDataURI)) ||
+      !isDataURI) {
+    int64_t length;
+    if (NS_SUCCEEDED(mChannel->GetContentLength(&length))) {
+      aResponseHeaders.AppendLiteral("Content-Length: ");
+      aResponseHeaders.AppendInt(length);
+      aResponseHeaders.AppendLiteral("\r\n");
+    }
+  }
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetResponseHeader(const nsACString& aHeader,
+                                            nsACString& aResult)
+{
+  ErrorResult rv;
+  GetResponseHeader(aHeader, aResult, rv);
+  return rv.StealNSResult();
+}
+
+void
+XMLHttpRequestMainThread::GetResponseHeader(const nsACString& header,
+                                            nsACString& _retval, ErrorResult& aRv)
+{
+  _retval.SetIsVoid(true);
+
+  nsCOMPtr<nsIHttpChannel> httpChannel = GetCurrentHttpChannel();
+
+  if (!httpChannel) {
+    // If the state is UNSENT or OPENED,
+    // return null and terminate these steps.
+    if (mState == State::unsent || mState == State::opened) {
+      return;
+    }
+
+    // Even non-http channels supply content type and content length.
+    // Remember we don't leak header information from denied cross-site
+    // requests.
+    nsresult status;
+    if (!mChannel ||
+        NS_FAILED(mChannel->GetStatus(&status)) ||
+        NS_FAILED(status)) {
+      return;
+    }
+
+    // Content Type:
+    if (header.LowerCaseEqualsASCII("content-type")) {
+      if (NS_FAILED(mChannel->GetContentType(_retval))) {
+        // Means no content type
+        _retval.SetIsVoid(true);
+        return;
+      }
+
+      nsCString value;
+      if (NS_SUCCEEDED(mChannel->GetContentCharset(value)) &&
+          !value.IsEmpty()) {
+        _retval.AppendLiteral(";charset=");
+        _retval.Append(value);
+      }
+    }
+
+    // Content Length:
+    else if (header.LowerCaseEqualsASCII("content-length")) {
+      int64_t length;
+      if (NS_SUCCEEDED(mChannel->GetContentLength(&length))) {
+        _retval.AppendInt(length);
+      }
+    }
+
+    return;
+  }
+
+  // Check for dangerous headers
+  if (!IsSafeHeader(header, WrapNotNull(httpChannel))) {
+    return;
+  }
+
+  aRv = httpChannel->GetResponseHeader(header, _retval);
+  if (aRv.ErrorCodeIs(NS_ERROR_NOT_AVAILABLE)) {
+    // Means no header
+    _retval.SetIsVoid(true);
+    aRv.SuppressException();
+  }
+}
+
+already_AddRefed<nsILoadGroup>
+XMLHttpRequestMainThread::GetLoadGroup() const
+{
+  if (mFlagBackgroundRequest) {
+    return nullptr;
+  }
+
+  if (mLoadGroup) {
+    nsCOMPtr<nsILoadGroup> ref = mLoadGroup;
+    return ref.forget();
+  }
+
+  nsIDocument* doc = GetDocumentIfCurrent();
+  if (doc) {
+    return doc->GetDocumentLoadGroup();
+  }
+
+  return nullptr;
+}
+
+nsresult
+XMLHttpRequestMainThread::FireReadystatechangeEvent()
+{
+  RefPtr<Event> event = NS_NewDOMEvent(this, nullptr, nullptr);
+  event->InitEvent(kLiteralString_readystatechange, false, false);
+  // We assume anyone who managed to call CreateReadystatechangeEvent is trusted
+  event->SetTrusted(true);
+  DispatchDOMEvent(nullptr, event, nullptr, nullptr);
+  return NS_OK;
+}
+
+void
+XMLHttpRequestMainThread::DispatchProgressEvent(DOMEventTargetHelper* aTarget,
+                                                const ProgressEventType aType,
+                                                int64_t aLoaded, int64_t aTotal)
+{
+  NS_ASSERTION(aTarget, "null target");
+
+  if (NS_FAILED(CheckInnerWindowCorrectness()) ||
+      (!AllowUploadProgress() && aTarget == mUpload)) {
+    return;
+  }
+
+  // If blocked by CORS, zero-out the stats on progress events
+  // and never fire "progress" or "load" events at all.
+  if (IsDeniedCrossSiteCORSRequest()) {
+    if (aType == ProgressEventType::progress ||
+        aType == ProgressEventType::load) {
+      return;
+    }
+    aLoaded = 0;
+    aTotal = -1;
+  }
+
+  if (aType == ProgressEventType::progress) {
+    mInLoadProgressEvent = true;
+  }
+
+  ProgressEventInit init;
+  init.mBubbles = false;
+  init.mCancelable = false;
+  init.mLengthComputable = aTotal != -1; // XHR spec step 6.1
+  init.mLoaded = aLoaded;
+  init.mTotal = (aTotal == -1) ? 0 : aTotal;
+
+  const nsAString& typeString = ProgressEventTypeStrings[(uint8_t)aType];
+  RefPtr<ProgressEvent> event =
+    ProgressEvent::Constructor(aTarget, typeString, init);
+  event->SetTrusted(true);
+
+  aTarget->DispatchDOMEvent(nullptr, event, nullptr, nullptr);
+
+  if (aType == ProgressEventType::progress) {
+    mInLoadProgressEvent = false;
+
+    // clear chunked responses after every progress event
+    if (mResponseType == XMLHttpRequestResponseType::Moz_chunked_text ||
+        mResponseType == XMLHttpRequestResponseType::Moz_chunked_arraybuffer) {
+      mResponseBody.Truncate();
+      TruncateResponseText();
+      mResultArrayBuffer = nullptr;
+      mArrayBufferBuilder.reset();
+    }
+  }
+
+  // If we're sending a load, error, timeout or abort event, then
+  // also dispatch the subsequent loadend event.
+  if (aType == ProgressEventType::load || aType == ProgressEventType::error ||
+      aType == ProgressEventType::timeout || aType == ProgressEventType::abort) {
+    DispatchProgressEvent(aTarget, ProgressEventType::loadend, aLoaded, aTotal);
+  }
+}
+
+already_AddRefed<nsIHttpChannel>
+XMLHttpRequestMainThread::GetCurrentHttpChannel()
+{
+  nsCOMPtr<nsIHttpChannel> httpChannel = do_QueryInterface(mChannel);
+  return httpChannel.forget();
+}
+
+already_AddRefed<nsIJARChannel>
+XMLHttpRequestMainThread::GetCurrentJARChannel()
+{
+  nsCOMPtr<nsIJARChannel> appChannel = do_QueryInterface(mChannel);
+  return appChannel.forget();
+}
+
+bool
+XMLHttpRequestMainThread::IsSystemXHR() const
+{
+  return mIsSystem || nsContentUtils::IsSystemPrincipal(mPrincipal);
+}
+ 
+bool
+XMLHttpRequestMainThread::InUploadPhase() const
+{
+  // We're in the upload phase while our state is State::opened.
+  return mState == State::opened;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::Open(const nsACString& aMethod, const nsACString& aUrl,
+                               bool aAsync, const nsAString& aUsername,
+                               const nsAString& aPassword, uint8_t optional_argc)
+{
+  return Open(aMethod, aUrl, optional_argc > 0 ? aAsync : true,
+              aUsername, aPassword);
+}
+
+// This case is hit when the async parameter is outright omitted, which
+// should set it to true (and the username and password to null).
+void
+XMLHttpRequestMainThread::Open(const nsACString& aMethod, const nsAString& aUrl,
+                               ErrorResult& aRv)
+{
+  Open(aMethod, aUrl, true, NullString(), NullString(), aRv);
+}
+
+// This case is hit when the async parameter is specified, even if the
+// JS value was "undefined" (which due to legacy reasons should be
+// treated as true, which is how it will already be passed in here).
+void
+XMLHttpRequestMainThread::Open(const nsACString& aMethod,
+                               const nsAString& aUrl,
+                               bool aAsync,
+                               const nsAString& aUsername,
+                               const nsAString& aPassword,
+                               ErrorResult& aRv)
+{
+  nsresult rv = Open(aMethod, NS_ConvertUTF16toUTF8(aUrl), aAsync, aUsername, aPassword);
+  if (NS_FAILED(rv)) {
+    aRv.Throw(rv);
+  }
+}
+
+nsresult
+XMLHttpRequestMainThread::Open(const nsACString& aMethod,
+                               const nsACString& aUrl,
+                               bool aAsync,
+                               const nsAString& aUsername,
+                               const nsAString& aPassword) {
+  // Gecko-specific
+  if (!aAsync && !DontWarnAboutSyncXHR() && GetOwner() &&
+      GetOwner()->GetExtantDoc()) {
+    GetOwner()->GetExtantDoc()->WarnOnceAbout(nsIDocument::eSyncXMLHttpRequest);
+  }
+
+  Telemetry::Accumulate(Telemetry::XMLHTTPREQUEST_ASYNC_OR_SYNC, aAsync ? 0 : 1);
+
+  // Step 1
+  nsCOMPtr<nsIDocument> responsibleDocument = GetDocumentIfCurrent();
+  if (!responsibleDocument) {
+    // This could be because we're no longer current or because we're in some
+    // non-window context...
+    nsresult rv = CheckInnerWindowCorrectness();
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return NS_ERROR_DOM_INVALID_STATE_XHR_HAS_INVALID_CONTEXT;
+    }
+  }
+  NS_ENSURE_TRUE(mPrincipal, NS_ERROR_NOT_INITIALIZED);
+
+  // Steps 2-4
+  nsAutoCString method;
+  nsresult rv = FetchUtil::GetValidRequestMethod(aMethod, method);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  // Steps 5-6
+  nsCOMPtr<nsIURI> baseURI;
+  if (mBaseURI) {
+    baseURI = mBaseURI;
+  } else if (responsibleDocument) {
+    baseURI = responsibleDocument->GetBaseURI();
+  }
+  nsCOMPtr<nsIURI> parsedURL;
+  rv = NS_NewURI(getter_AddRefs(parsedURL), aUrl, nullptr, baseURI);
+  if (NS_FAILED(rv)) {
+    if (rv ==  NS_ERROR_MALFORMED_URI) {
+      return NS_ERROR_DOM_MALFORMED_URI;
+    }
+    return rv;
+  }
+  if (NS_WARN_IF(NS_FAILED(CheckInnerWindowCorrectness()))) {
+    return NS_ERROR_DOM_INVALID_STATE_XHR_HAS_INVALID_CONTEXT;
+  }
+
+  // Step 7
+  // This is already handled by the other Open() method, which passes
+  // username and password in as NullStrings.
+
+  // Step 8
+  nsAutoCString host;
+  parsedURL->GetHost(host);
+  if (!host.IsEmpty()) {
+    nsAutoCString userpass;
+    if (!aUsername.IsVoid()) {
+      CopyUTF16toUTF8(aUsername, userpass);
+    }
+    userpass.AppendLiteral(":");
+    if (!aPassword.IsVoid()) {
+      AppendUTF16toUTF8(aPassword, userpass);
+    }
+    parsedURL->SetUserPass(userpass);
+  }
+
+  // Step 9
+  if (!aAsync && HasOrHasHadOwner() && (mTimeoutMilliseconds ||
+       mResponseType != XMLHttpRequestResponseType::_empty)) {
+    if (mTimeoutMilliseconds) {
+      LogMessage("TimeoutSyncXHRWarning", GetOwner());
+    }
+    if (mResponseType != XMLHttpRequestResponseType::_empty) {
+      LogMessage("ResponseTypeSyncXHRWarning", GetOwner());
+    }
+    return NS_ERROR_DOM_INVALID_ACCESS_XHR_TIMEOUT_AND_RESPONSETYPE_UNSUPPORTED_FOR_SYNC;
+  }
+
+  // Step 10
+  CloseRequest();
+
+  // Step 11
+  // timeouts are handled without a flag
+  mFlagSend = false;
+  mRequestMethod.Assign(method);
+  mRequestURL = parsedURL;
+  mFlagSynchronous = !aAsync;
+  mAuthorRequestHeaders.Clear();
+  ResetResponse();
+
+  // Gecko-specific
+  mFlagHadUploadListenersOnSend = false;
+  mFlagAborted = false;
+  mFlagTimedOut = false;
+
+  // Per spec we should only create the channel on send(), but we have internal
+  // code that relies on the channel being created now, and that code is not
+  // always IsSystemXHR(). However, we're not supposed to throw channel-creation
+  // errors during open(), so we silently ignore those here.
+  CreateChannel();
+
+  // Step 12
+  if (mState != State::opened) {
+    mState = State::opened;
+    FireReadystatechangeEvent();
+  }
+
+  return NS_OK;
+}
+
+void
+XMLHttpRequestMainThread::SetOriginAttributes(const OriginAttributesDictionary& aAttrs)
+{
+  MOZ_ASSERT((mState == State::opened) && !mFlagSend);
+
+  GenericOriginAttributes attrs(aAttrs);
+  NeckoOriginAttributes neckoAttrs;
+  neckoAttrs.SetFromGenericAttributes(attrs);
+
+  nsCOMPtr<nsILoadInfo> loadInfo = mChannel->GetLoadInfo();
+  MOZ_ASSERT(loadInfo);
+  loadInfo->SetOriginAttributes(neckoAttrs);
+}
+
+void
+XMLHttpRequestMainThread::PopulateNetworkInterfaceId()
+{
+  if (mNetworkInterfaceId.IsEmpty()) {
+    return;
+  }
+  nsCOMPtr<nsIHttpChannelInternal> channel(do_QueryInterface(mChannel));
+  if (!channel) {
+    return;
+  }
+  channel->SetNetworkInterfaceId(mNetworkInterfaceId);
+}
+
+/*
+ * "Copy" from a stream.
+ */
+nsresult
+XMLHttpRequestMainThread::StreamReaderFunc(nsIInputStream* in,
+                                           void* closure,
+                                           const char* fromRawSegment,
+                                           uint32_t toOffset,
+                                           uint32_t count,
+                                           uint32_t *writeCount)
+{
+  XMLHttpRequestMainThread* xmlHttpRequest = static_cast<XMLHttpRequestMainThread*>(closure);
+  if (!xmlHttpRequest || !writeCount) {
+    NS_WARNING("XMLHttpRequest cannot read from stream: no closure or writeCount");
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult rv = NS_OK;
+
+  if (xmlHttpRequest->mResponseType == XMLHttpRequestResponseType::Blob) {
+    if (!xmlHttpRequest->mDOMBlob) {
+      xmlHttpRequest->MaybeCreateBlobStorage();
+      rv = xmlHttpRequest->mBlobStorage->Append(fromRawSegment, count);
+    }
+  } else if (xmlHttpRequest->mResponseType == XMLHttpRequestResponseType::Moz_blob) {
+    if (!xmlHttpRequest->mDOMBlob) {
+      if (!xmlHttpRequest->mBlobSet) {
+        xmlHttpRequest->mBlobSet = new BlobSet();
+      }
+      rv = xmlHttpRequest->mBlobSet->AppendVoidPtr(fromRawSegment, count);
+    }
+    // Clear the cache so that the blob size is updated.
+    xmlHttpRequest->mResponseBlob = nullptr;
+  } else if ((xmlHttpRequest->mResponseType == XMLHttpRequestResponseType::Arraybuffer &&
+              !xmlHttpRequest->mIsMappedArrayBuffer) ||
+             xmlHttpRequest->mResponseType == XMLHttpRequestResponseType::Moz_chunked_arraybuffer) {
+    // get the initial capacity to something reasonable to avoid a bunch of reallocs right
+    // at the start
+    if (xmlHttpRequest->mArrayBufferBuilder.capacity() == 0)
+      xmlHttpRequest->mArrayBufferBuilder.setCapacity(std::max(count, XML_HTTP_REQUEST_ARRAYBUFFER_MIN_SIZE));
+
+    xmlHttpRequest->mArrayBufferBuilder.append(reinterpret_cast<const uint8_t*>(fromRawSegment), count,
+                                               XML_HTTP_REQUEST_ARRAYBUFFER_MAX_GROWTH);
+  } else if (xmlHttpRequest->mResponseType == XMLHttpRequestResponseType::_empty &&
+             xmlHttpRequest->mResponseXML) {
+    // Copy for our own use
+    if (!xmlHttpRequest->mResponseBody.Append(fromRawSegment, count, fallible)) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+  } else if (xmlHttpRequest->mResponseType == XMLHttpRequestResponseType::_empty ||
+             xmlHttpRequest->mResponseType == XMLHttpRequestResponseType::Text ||
+             xmlHttpRequest->mResponseType == XMLHttpRequestResponseType::Json ||
+             xmlHttpRequest->mResponseType == XMLHttpRequestResponseType::Moz_chunked_text) {
+    NS_ASSERTION(!xmlHttpRequest->mResponseXML,
+                 "We shouldn't be parsing a doc here");
+    xmlHttpRequest->AppendToResponseText(fromRawSegment, count);
+  }
+
+  if (xmlHttpRequest->mFlagParseBody) {
+    // Give the same data to the parser.
+
+    // We need to wrap the data in a new lightweight stream and pass that
+    // to the parser, because calling ReadSegments() recursively on the same
+    // stream is not supported.
+    nsCOMPtr<nsIInputStream> copyStream;
+    rv = NS_NewByteInputStream(getter_AddRefs(copyStream), fromRawSegment, count);
+
+    if (NS_SUCCEEDED(rv) && xmlHttpRequest->mXMLParserStreamListener) {
+      NS_ASSERTION(copyStream, "NS_NewByteInputStream lied");
+      nsresult parsingResult = xmlHttpRequest->mXMLParserStreamListener
+                                  ->OnDataAvailable(xmlHttpRequest->mChannel,
+                                                    xmlHttpRequest->mContext,
+                                                    copyStream, toOffset, count);
+
+      // No use to continue parsing if we failed here, but we
+      // should still finish reading the stream
+      if (NS_FAILED(parsingResult)) {
+        xmlHttpRequest->mFlagParseBody = false;
+      }
+    }
+  }
+
+  if (NS_SUCCEEDED(rv)) {
+    *writeCount = count;
+  } else {
+    *writeCount = 0;
+  }
+
+  return rv;
+}
+
+bool XMLHttpRequestMainThread::CreateDOMBlob(nsIRequest *request)
+{
+  nsCOMPtr<nsIFile> file;
+  nsCOMPtr<nsIFileChannel> fc = do_QueryInterface(request);
+  if (fc) {
+    fc->GetFile(getter_AddRefs(file));
+  }
+
+  if (!file)
+    return false;
+
+  nsAutoCString contentType;
+  mChannel->GetContentType(contentType);
+
+  mDOMBlob = File::CreateFromFile(GetOwner(), file, EmptyString(),
+                                  NS_ConvertASCIItoUTF16(contentType));
+
+  mBlobStorage = nullptr;
+  mBlobSet = nullptr;
+  NS_ASSERTION(mResponseBody.IsEmpty(), "mResponseBody should be empty");
+  return true;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::OnDataAvailable(nsIRequest *request,
+                                          nsISupports *ctxt,
+                                          nsIInputStream *inStr,
+                                          uint64_t sourceOffset,
+                                          uint32_t count)
+{
+  NS_ENSURE_ARG_POINTER(inStr);
+
+  MOZ_ASSERT(mContext.get() == ctxt,"start context different from OnDataAvailable context");
+
+  mProgressSinceLastProgressEvent = true;
+  XMLHttpRequestBinding::ClearCachedResponseTextValue(this);
+
+  bool cancelable = false;
+  if ((mResponseType == XMLHttpRequestResponseType::Blob ||
+       mResponseType == XMLHttpRequestResponseType::Moz_blob) && !mDOMBlob) {
+    cancelable = CreateDOMBlob(request);
+    // The nsIStreamListener contract mandates us
+    // to read from the stream before returning.
+  }
+
+  uint32_t totalRead;
+  nsresult rv = inStr->ReadSegments(XMLHttpRequestMainThread::StreamReaderFunc,
+                                    (void*)this, count, &totalRead);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (cancelable) {
+    // We don't have to read from the local file for the blob response
+    ErrorResult error;
+    mDataAvailable = mDOMBlob->GetSize(error);
+    if (NS_WARN_IF(error.Failed())) {
+      return error.StealNSResult();
+    }
+
+    ChangeState(State::loading);
+    return request->Cancel(NS_OK);
+  }
+
+  mDataAvailable += totalRead;
+
+  // Fire the first progress event/loading state change
+  if (mState != State::loading) {
+    ChangeState(State::loading);
+    if (!mFlagSynchronous) {
+      DispatchProgressEvent(this, ProgressEventType::progress,
+                            mLoadTransferred, mLoadTotal);
+    }
+    mProgressSinceLastProgressEvent = false;
+  }
+
+  if (!mFlagSynchronous && !mProgressTimerIsActive) {
+    StartProgressEventTimer();
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::OnStartRequest(nsIRequest *request, nsISupports *ctxt)
+{
+  PROFILER_LABEL("XMLHttpRequestMainThread", "OnStartRequest",
+    js::ProfileEntry::Category::NETWORK);
+
+  nsresult rv = NS_OK;
+  if (!mFirstStartRequestSeen && mRequestObserver) {
+    mFirstStartRequestSeen = true;
+    mRequestObserver->OnStartRequest(request, ctxt);
+  }
+
+  if (request != mChannel) {
+    // Can this still happen?
+    return NS_OK;
+  }
+
+  // Don't do anything if we have been aborted
+  if (mState == State::unsent) {
+    return NS_OK;
+  }
+
+  /* Apparently, Abort() should set State::unsent.  See bug 361773.
+     XHR2 spec says this is correct. */
+  if (mFlagAborted) {
+    NS_ERROR("Ugh, still getting data on an aborted XMLHttpRequest!");
+
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  // Don't do anything if we have timed out.
+  if (mFlagTimedOut) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIChannel> channel(do_QueryInterface(request));
+  NS_ENSURE_TRUE(channel, NS_ERROR_UNEXPECTED);
+
+  nsresult status;
+  request->GetStatus(&status);
+  mErrorLoad = mErrorLoad || NS_FAILED(status);
+
+  // Upload phase is now over. If we were uploading anything,
+  // stop the timer and fire any final progress events.
+  if (mUpload && !mUploadComplete && !mErrorLoad && !mFlagSynchronous) {
+    StopProgressEventTimer();
+
+    mUploadTransferred = mUploadTotal;
+
+    if (mProgressSinceLastProgressEvent) {
+      DispatchProgressEvent(mUpload, ProgressEventType::progress,
+                            mUploadTransferred, mUploadTotal);
+      mProgressSinceLastProgressEvent = false;
+    }
+
+    mUploadComplete = true;
+    DispatchProgressEvent(mUpload, ProgressEventType::load,
+                          mUploadTotal, mUploadTotal);
+  }
+
+  mContext = ctxt;
+  mFlagParseBody = true;
+  ChangeState(State::headers_received);
+
+  ResetResponse();
+
+  if (!mOverrideMimeType.IsEmpty()) {
+    channel->SetContentType(NS_ConvertUTF16toUTF8(mOverrideMimeType));
+  }
+
+  DetectCharset();
+
+  // Set up arraybuffer
+  if (mResponseType == XMLHttpRequestResponseType::Arraybuffer &&
+      NS_SUCCEEDED(status)) {
+    if (mIsMappedArrayBuffer) {
+      nsCOMPtr<nsIJARChannel> jarChannel = do_QueryInterface(channel);
+      if (jarChannel) {
+        nsCOMPtr<nsIURI> uri;
+        rv = channel->GetURI(getter_AddRefs(uri));
+        if (NS_SUCCEEDED(rv)) {
+          nsAutoCString file;
+          nsAutoCString scheme;
+          uri->GetScheme(scheme);
+          if (scheme.LowerCaseEqualsLiteral("jar")) {
+            nsCOMPtr<nsIJARURI> jarURI = do_QueryInterface(uri);
+            if (jarURI) {
+              jarURI->GetJAREntry(file);
+            }
+          }
+          nsCOMPtr<nsIFile> jarFile;
+          jarChannel->GetJarFile(getter_AddRefs(jarFile));
+          if (!jarFile) {
+            mIsMappedArrayBuffer = false;
+          } else {
+            rv = mArrayBufferBuilder.mapToFileInPackage(file, jarFile);
+            if (NS_WARN_IF(NS_FAILED(rv))) {
+              mIsMappedArrayBuffer = false;
+            } else {
+              channel->SetContentType(NS_LITERAL_CSTRING("application/mem-mapped"));
+            }
+          }
+        }
+      }
+    }
+    // If memory mapping failed, mIsMappedArrayBuffer would be set to false,
+    // and we want it fallback to the malloc way.
+    if (!mIsMappedArrayBuffer) {
+      int64_t contentLength;
+      rv = channel->GetContentLength(&contentLength);
+      if (NS_SUCCEEDED(rv) &&
+          contentLength > 0 &&
+          contentLength < XML_HTTP_REQUEST_MAX_CONTENT_LENGTH_PREALLOCATE) {
+        mArrayBufferBuilder.setCapacity(static_cast<int32_t>(contentLength));
+      }
+    }
+  }
+
+  // Set up responseXML
+  bool parseBody = mResponseType == XMLHttpRequestResponseType::_empty ||
+                   mResponseType == XMLHttpRequestResponseType::Document;
+  nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(mChannel));
+  if (parseBody && httpChannel) {
+    nsAutoCString method;
+    httpChannel->GetRequestMethod(method);
+    parseBody = !method.EqualsLiteral("HEAD");
+  }
+
+  mIsHtml = false;
+  mWarnAboutSyncHtml = false;
+  if (parseBody && NS_SUCCEEDED(status)) {
+    // We can gain a huge performance win by not even trying to
+    // parse non-XML data. This also protects us from the situation
+    // where we have an XML document and sink, but HTML (or other)
+    // parser, which can produce unreliable results.
+    nsAutoCString type;
+    channel->GetContentType(type);
+
+    if ((mResponseType == XMLHttpRequestResponseType::Document) &&
+        type.EqualsLiteral("text/html")) {
+      // HTML parsing is only supported for responseType == "document" to
+      // avoid running the parser and, worse, populating responseXML for
+      // legacy users of XHR who use responseType == "" for retrieving the
+      // responseText of text/html resources. This legacy case is so common
+      // that it's not useful to emit a warning about it.
+      if (mFlagSynchronous) {
+        // We don't make cool new features available in the bad synchronous
+        // mode. The synchronous mode is for legacy only.
+        mWarnAboutSyncHtml = true;
+        mFlagParseBody = false;
+      } else {
+        mIsHtml = true;
+      }
+    } else if (!(type.EqualsLiteral("text/xml") ||
+                 type.EqualsLiteral("application/xml") ||
+                 type.RFind("+xml", true, -1, 4) != kNotFound)) {
+      // Follow https://xhr.spec.whatwg.org/
+      // If final MIME type is not null, text/html, text/xml, application/xml,
+      // or does not end in +xml, return null.
+      mFlagParseBody = false;
+    }
+  } else {
+    // The request failed, so we shouldn't be parsing anyway
+    mFlagParseBody = false;
+  }
+
+  if (mFlagParseBody) {
+    nsCOMPtr<nsIURI> baseURI, docURI;
+    rv = mChannel->GetURI(getter_AddRefs(docURI));
+    NS_ENSURE_SUCCESS(rv, rv);
+    baseURI = docURI;
+
+    nsCOMPtr<nsIDocument> doc = GetDocumentIfCurrent();
+    nsCOMPtr<nsIURI> chromeXHRDocURI, chromeXHRDocBaseURI;
+    if (doc) {
+      chromeXHRDocURI = doc->GetDocumentURI();
+      chromeXHRDocBaseURI = doc->GetBaseURI();
+    } else {
+      // If we're no longer current, just kill the load, though it really should
+      // have been killed already.
+      if (NS_WARN_IF(NS_FAILED(CheckInnerWindowCorrectness()))) {
+        return NS_ERROR_DOM_INVALID_STATE_XHR_HAS_INVALID_CONTEXT;
+      }
+    }
+
+    // Create an empty document from it.
+    const nsAString& emptyStr = EmptyString();
+    nsCOMPtr<nsIDOMDocument> responseDoc;
+    nsIGlobalObject* global = DOMEventTargetHelper::GetParentObject();
+
+    nsCOMPtr<nsIPrincipal> requestingPrincipal;
+    rv = nsContentUtils::GetSecurityManager()->
+       GetChannelResultPrincipal(channel, getter_AddRefs(requestingPrincipal));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    rv = NS_NewDOMDocument(getter_AddRefs(responseDoc),
+                           emptyStr, emptyStr, nullptr, docURI,
+                           baseURI, requestingPrincipal, true, global,
+                           mIsHtml ? DocumentFlavorHTML :
+                                     DocumentFlavorLegacyGuess);
+    NS_ENSURE_SUCCESS(rv, rv);
+    mResponseXML = do_QueryInterface(responseDoc);
+    mResponseXML->SetChromeXHRDocURI(chromeXHRDocURI);
+    mResponseXML->SetChromeXHRDocBaseURI(chromeXHRDocBaseURI);
+
+    if (nsContentUtils::IsSystemPrincipal(mPrincipal)) {
+      mResponseXML->ForceEnableXULXBL();
+    }
+
+    nsCOMPtr<nsILoadInfo> loadInfo = mChannel->GetLoadInfo();
+    MOZ_ASSERT(loadInfo);
+    bool isCrossSite = loadInfo->GetTainting() != LoadTainting::Basic;
+
+    if (isCrossSite) {
+      nsCOMPtr<nsIHTMLDocument> htmlDoc = do_QueryInterface(mResponseXML);
+      if (htmlDoc) {
+        htmlDoc->DisableCookieAccess();
+      }
+    }
+
+    nsCOMPtr<nsIStreamListener> listener;
+    nsCOMPtr<nsILoadGroup> loadGroup;
+    channel->GetLoadGroup(getter_AddRefs(loadGroup));
+
+    // suppress <parsererror> nodes on XML document parse failure, but only
+    // for non-privileged code (including Web Extensions). See bug 289714.
+    if (!IsSystemXHR()) {
+      mResponseXML->SetSuppressParserErrorElement(true);
+    }
+
+    rv = mResponseXML->StartDocumentLoad(kLoadAsData, channel, loadGroup,
+                                         nullptr, getter_AddRefs(listener),
+                                         !isCrossSite);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // the spec requires the response document.referrer to be the empty string
+    mResponseXML->SetReferrer(NS_LITERAL_CSTRING(""));
+
+    mXMLParserStreamListener = listener;
+    rv = mXMLParserStreamListener->OnStartRequest(request, ctxt);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  // Download phase beginning; start the progress event timer if necessary.
+  if (NS_SUCCEEDED(rv) && HasListenersFor(nsGkAtoms::onprogress)) {
+    StartProgressEventTimer();
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::OnStopRequest(nsIRequest *request, nsISupports *ctxt, nsresult status)
+{
+  PROFILER_LABEL("XMLHttpRequestMainThread", "OnStopRequest",
+    js::ProfileEntry::Category::NETWORK);
+
+  if (request != mChannel) {
+    // Can this still happen?
+    return NS_OK;
+  }
+
+  mWaitingForOnStopRequest = false;
+
+  if (mRequestObserver) {
+    NS_ASSERTION(mFirstStartRequestSeen, "Inconsistent state!");
+    mFirstStartRequestSeen = false;
+    mRequestObserver->OnStopRequest(request, ctxt, status);
+  }
+
+  // suppress parsing failure messages to console for status 204/304 (see bug 884693).
+  if (mResponseXML) {
+    uint32_t responseStatus;
+    if (NS_SUCCEEDED(GetStatus(&responseStatus)) &&
+        (responseStatus == 204 || responseStatus == 304)) {
+      mResponseXML->SetSuppressParserErrorConsoleMessages(true);
+    }
+  }
+
+  // make sure to notify the listener if we were aborted
+  // XXX in fact, why don't we do the cleanup below in this case??
+  // State::unsent is for abort calls.  See OnStartRequest above.
+  if (mState == State::unsent || mFlagTimedOut) {
+    if (mXMLParserStreamListener)
+      (void) mXMLParserStreamListener->OnStopRequest(request, ctxt, status);
+    return NS_OK;
+  }
+
+  // Is this good enough here?
+  if (mXMLParserStreamListener && mFlagParseBody) {
+    mXMLParserStreamListener->OnStopRequest(request, ctxt, status);
+  }
+
+  mXMLParserStreamListener = nullptr;
+  mContext = nullptr;
+
+  bool waitingForBlobCreation = false;
+
+  if (NS_SUCCEEDED(status) &&
+      (mResponseType == XMLHttpRequestResponseType::Blob ||
+       mResponseType == XMLHttpRequestResponseType::Moz_blob)) {
+    ErrorResult rv;
+    if (!mDOMBlob) {
+      CreateDOMBlob(request);
+    }
+    if (mDOMBlob) {
+      mResponseBlob = mDOMBlob;
+      mDOMBlob = nullptr;
+    } else {
+      // Smaller files may be written in cache map instead of separate files.
+      // Also, no-store response cannot be written in persistent cache.
+      nsAutoCString contentType;
+      mChannel->GetContentType(contentType);
+
+      if (mResponseType == XMLHttpRequestResponseType::Blob) {
+        // mBlobStorage can be null if the channel is non-file non-cacheable
+        // and if the response length is zero.
+        MaybeCreateBlobStorage();
+        mBlobStorage->GetBlobWhenReady(GetOwner(), contentType, this);
+        waitingForBlobCreation = true;
+      } else {
+        // mBlobSet can be null if the channel is non-file non-cacheable
+        // and if the response length is zero.
+        if (!mBlobSet) {
+          mBlobSet = new BlobSet();
+        }
+
+        nsTArray<RefPtr<BlobImpl>> subImpls(mBlobSet->GetBlobImpls());
+        RefPtr<BlobImpl> blobImpl =
+          MultipartBlobImpl::Create(Move(subImpls),
+                                    NS_ConvertASCIItoUTF16(contentType),
+                                    rv);
+        mBlobSet = nullptr;
+
+        if (NS_WARN_IF(rv.Failed())) {
+          return rv.StealNSResult();
+        }
+
+        mResponseBlob = Blob::Create(GetOwner(), blobImpl);
+      }
+    }
+
+    NS_ASSERTION(mResponseBody.IsEmpty(), "mResponseBody should be empty");
+    NS_ASSERTION(mResponseText.IsEmpty(), "mResponseText should be empty");
+  } else if (NS_SUCCEEDED(status) &&
+             ((mResponseType == XMLHttpRequestResponseType::Arraybuffer &&
+               !mIsMappedArrayBuffer) ||
+              mResponseType == XMLHttpRequestResponseType::Moz_chunked_arraybuffer)) {
+    // set the capacity down to the actual length, to realloc back
+    // down to the actual size
+    if (!mArrayBufferBuilder.setCapacity(mArrayBufferBuilder.length())) {
+      // this should never happen!
+      status = NS_ERROR_UNEXPECTED;
+    }
+  }
+
+  nsCOMPtr<nsIChannel> channel(do_QueryInterface(request));
+  NS_ENSURE_TRUE(channel, NS_ERROR_UNEXPECTED);
+
+  channel->SetNotificationCallbacks(nullptr);
+  mNotificationCallbacks = nullptr;
+  mChannelEventSink = nullptr;
+  mProgressEventSink = nullptr;
+
+  mFlagSyncLooping = false;
+
+  // update our charset and decoder to match mResponseXML,
+  // before it is possibly nulled out
+  MatchCharsetAndDecoderToResponseDocument();
+
+  if (NS_FAILED(status)) {
+    // This can happen if the server is unreachable. Other possible
+    // reasons are that the user leaves the page or hits the ESC key.
+
+    mErrorLoad = true;
+    mResponseXML = nullptr;
+  }
+
+  // If we're uninitialized at this point, we encountered an error
+  // earlier and listeners have already been notified. Also we do
+  // not want to do this if we already completed.
+  if (mState == State::unsent || mState == State::done) {
+    return NS_OK;
+  }
+
+  if (!mResponseXML) {
+    mFlagParseBody = false;
+
+    //We postpone the 'done' until the creation of the Blob is completed.
+    if (!waitingForBlobCreation) {
+      ChangeStateToDone();
+    }
+
+    return NS_OK;
+  }
+
+  if (mIsHtml) {
+    NS_ASSERTION(!mFlagSyncLooping,
+      "We weren't supposed to support HTML parsing with XHR!");
+    nsCOMPtr<EventTarget> eventTarget = do_QueryInterface(mResponseXML);
+    EventListenerManager* manager =
+      eventTarget->GetOrCreateListenerManager();
+    manager->AddEventListenerByType(new nsXHRParseEndListener(this),
+                                    kLiteralString_DOMContentLoaded,
+                                    TrustedEventsAtSystemGroupBubble());
+    return NS_OK;
+  } else {
+    mFlagParseBody = false;
+  }
+
+  // We might have been sent non-XML data. If that was the case,
+  // we should null out the document member. The idea in this
+  // check here is that if there is no document element it is not
+  // an XML document. We might need a fancier check...
+  if (!mResponseXML->GetRootElement()) {
+    mErrorParsingXML = true;
+    mResponseXML = nullptr;
+  }
+  ChangeStateToDone();
+  return NS_OK;
+}
+
+void
+XMLHttpRequestMainThread::OnBodyParseEnd()
+{
+  mFlagParseBody = false;
+  ChangeStateToDone();
+}
+
+void
+XMLHttpRequestMainThread::MatchCharsetAndDecoderToResponseDocument()
+{
+  if (mResponseXML && mResponseCharset != mResponseXML->GetDocumentCharacterSet()) {
+    mResponseCharset = mResponseXML->GetDocumentCharacterSet();
+    TruncateResponseText();
+    mResponseBodyDecodedPos = 0;
+    mDecoder = EncodingUtils::DecoderForEncoding(mResponseCharset);
+  }
+}
+
+void
+XMLHttpRequestMainThread::ChangeStateToDone()
+{
+  StopProgressEventTimer();
+
+  MOZ_ASSERT(!mFlagParseBody,
+             "ChangeStateToDone() called before async HTML parsing is done.");
+
+  mFlagSend = false;
+
+  if (mTimeoutTimer) {
+    mTimeoutTimer->Cancel();
+  }
+
+  // Per spec, fire the last download progress event, if any,
+  // before readystatechange=4/done. (Note that 0-sized responses
+  // will have not sent a progress event yet, so one must be sent here).
+  if (!mFlagSynchronous &&
+      (!mLoadTransferred || mProgressSinceLastProgressEvent)) {
+    DispatchProgressEvent(this, ProgressEventType::progress,
+                          mLoadTransferred, mLoadTotal);
+    mProgressSinceLastProgressEvent = false;
+  }
+
+  // Per spec, fire readystatechange=4/done before final error events.
+  ChangeState(State::done, true);
+
+  // Per spec, if we failed in the upload phase, fire a final error
+  // and loadend events for the upload after readystatechange=4/done.
+  if (!mFlagSynchronous && mUpload && !mUploadComplete) {
+    DispatchProgressEvent(mUpload, ProgressEventType::error, 0, -1);
+  }
+
+  // Per spec, fire download's load/error and loadend events after
+  // readystatechange=4/done (and of course all upload events).
+  DispatchProgressEvent(this,
+                        mErrorLoad ? ProgressEventType::error :
+                                     ProgressEventType::load,
+                        mErrorLoad ? 0 : mLoadTransferred,
+                        mErrorLoad ? -1 : mLoadTotal);
+
+  if (mErrorLoad) {
+    // By nulling out channel here we make it so that Send() can test
+    // for that and throw. Also calling the various status
+    // methods/members will not throw.
+    // This matches what IE does.
+    mChannel = nullptr;
+  }
+}
+
+template<> nsresult
+XMLHttpRequestMainThread::RequestBody<nsIDocument>::GetAsStream(
+   nsIInputStream** aResult, uint64_t* aContentLength,
+   nsACString& aContentType, nsACString& aCharset) const
+{
+  nsCOMPtr<nsIDOMDocument> domdoc(do_QueryInterface(mBody));
+  NS_ENSURE_STATE(domdoc);
+  aCharset.AssignLiteral("UTF-8");
+
+  nsresult rv;
+  nsCOMPtr<nsIStorageStream> storStream;
+  rv = NS_NewStorageStream(4096, UINT32_MAX, getter_AddRefs(storStream));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIOutputStream> output;
+  rv = storStream->GetOutputStream(0, getter_AddRefs(output));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (mBody->IsHTMLDocument()) {
+    aContentType.AssignLiteral("text/html");
+
+    nsString serialized;
+    if (!nsContentUtils::SerializeNodeToMarkup(mBody, true, serialized)) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    nsAutoCString utf8Serialized;
+    if (!AppendUTF16toUTF8(serialized, utf8Serialized, fallible)) {
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+
+    uint32_t written;
+    rv = output->Write(utf8Serialized.get(), utf8Serialized.Length(), &written);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    MOZ_ASSERT(written == utf8Serialized.Length());
+  } else {
+    aContentType.AssignLiteral("application/xml");
+
+    nsCOMPtr<nsIDOMSerializer> serializer =
+      do_CreateInstance(NS_XMLSERIALIZER_CONTRACTID, &rv);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // Make sure to use the encoding we'll send
+    rv = serializer->SerializeToStream(domdoc, output, aCharset);
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
+  output->Close();
+
+  uint32_t length;
+  rv = storStream->GetLength(&length);
+  NS_ENSURE_SUCCESS(rv, rv);
+  *aContentLength = length;
+
+  rv = storStream->NewInputStream(0, aResult);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return NS_OK;
+}
+
+template<> nsresult
+XMLHttpRequestMainThread::RequestBody<const nsAString>::GetAsStream(
+   nsIInputStream** aResult, uint64_t* aContentLength,
+   nsACString& aContentType, nsACString& aCharset) const
+{
+  aContentType.AssignLiteral("text/plain");
+  aCharset.AssignLiteral("UTF-8");
+
+  nsAutoCString converted;
+  if (!AppendUTF16toUTF8(*mBody, converted, fallible)) {
+    return NS_ERROR_OUT_OF_MEMORY;
+  }
+
+  *aContentLength = converted.Length();
+  nsresult rv = NS_NewCStringInputStream(aResult, converted);
+  NS_ENSURE_SUCCESS(rv, rv);
+  return NS_OK;
+}
+
+template<> nsresult
+XMLHttpRequestMainThread::RequestBody<nsIInputStream>::GetAsStream(
+   nsIInputStream** aResult, uint64_t* aContentLength,
+   nsACString& aContentType, nsACString& aCharset) const
+{
+  aContentType.AssignLiteral("text/plain");
+  aCharset.Truncate();
+
+  nsresult rv = mBody->Available(aContentLength);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIInputStream> stream(mBody);
+  stream.forget(aResult);
+  return NS_OK;
+}
+
+template<> nsresult
+XMLHttpRequestMainThread::RequestBody<Blob>::GetAsStream(
+   nsIInputStream** aResult, uint64_t* aContentLength,
+   nsACString& aContentType, nsACString& aCharset) const
+{
+  return mBody->GetSendInfo(aResult, aContentLength, aContentType, aCharset);
+}
+
+template<> nsresult
+XMLHttpRequestMainThread::RequestBody<FormData>::GetAsStream(
+   nsIInputStream** aResult, uint64_t* aContentLength,
+   nsACString& aContentType, nsACString& aCharset) const
+{
+  return mBody->GetSendInfo(aResult, aContentLength, aContentType, aCharset);
+}
+
+template<> nsresult
+XMLHttpRequestMainThread::RequestBody<URLSearchParams>::GetAsStream(
+   nsIInputStream** aResult, uint64_t* aContentLength,
+   nsACString& aContentType, nsACString& aCharset) const
+{
+  return mBody->GetSendInfo(aResult, aContentLength, aContentType, aCharset);
+}
+
+template<> nsresult
+XMLHttpRequestMainThread::RequestBody<nsIXHRSendable>::GetAsStream(
+   nsIInputStream** aResult, uint64_t* aContentLength,
+   nsACString& aContentType, nsACString& aCharset) const
+{
+  return mBody->GetSendInfo(aResult, aContentLength, aContentType, aCharset);
+}
+
+static nsresult
+GetBufferDataAsStream(const uint8_t* aData, uint32_t aDataLength,
+                      nsIInputStream** aResult, uint64_t* aContentLength,
+                      nsACString& aContentType, nsACString& aCharset)
+{
+  aContentType.SetIsVoid(true);
+  aCharset.Truncate();
+
+  *aContentLength = aDataLength;
+  const char* data = reinterpret_cast<const char*>(aData);
+
+  nsCOMPtr<nsIInputStream> stream;
+  nsresult rv = NS_NewByteInputStream(getter_AddRefs(stream), data, aDataLength,
+                                      NS_ASSIGNMENT_COPY);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  stream.forget(aResult);
+
+  return NS_OK;
+}
+
+template<> nsresult
+XMLHttpRequestMainThread::RequestBody<const ArrayBuffer>::GetAsStream(
+   nsIInputStream** aResult, uint64_t* aContentLength,
+   nsACString& aContentType, nsACString& aCharset) const
+{
+  mBody->ComputeLengthAndData();
+  return GetBufferDataAsStream(mBody->Data(), mBody->Length(),
+                               aResult, aContentLength, aContentType, aCharset);
+}
+
+template<> nsresult
+XMLHttpRequestMainThread::RequestBody<const ArrayBufferView>::GetAsStream(
+   nsIInputStream** aResult, uint64_t* aContentLength,
+   nsACString& aContentType, nsACString& aCharset) const
+{
+  mBody->ComputeLengthAndData();
+  return GetBufferDataAsStream(mBody->Data(), mBody->Length(),
+                               aResult, aContentLength, aContentType, aCharset);
+}
+
+
+nsresult
+XMLHttpRequestMainThread::CreateChannel()
+{
+  // When we are called from JS we can find the load group for the page,
+  // and add ourselves to it. This way any pending requests
+  // will be automatically aborted if the user leaves the page.
+  nsCOMPtr<nsILoadGroup> loadGroup = GetLoadGroup();
+
+  nsSecurityFlags secFlags;
+  nsLoadFlags loadFlags = nsIRequest::LOAD_BACKGROUND |
+                          nsIChannel::LOAD_CLASSIFY_URI;
+  if (nsContentUtils::IsSystemPrincipal(mPrincipal)) {
+    // When chrome is loading we want to make sure to sandbox any potential
+    // result document. We also want to allow cross-origin loads.
+    secFlags = nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_DATA_IS_NULL |
+               nsILoadInfo::SEC_SANDBOXED;
+  } else if (IsSystemXHR()) {
+    // For pages that have appropriate permissions, we want to still allow
+    // cross-origin loads, but make sure that the any potential result
+    // documents get the same principal as the loader.
+    secFlags = nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_DATA_INHERITS |
+               nsILoadInfo::SEC_FORCE_INHERIT_PRINCIPAL;
+    loadFlags |= nsIChannel::LOAD_BYPASS_SERVICE_WORKER;
+  } else {
+    // Otherwise use CORS. Again, make sure that potential result documents
+    // use the same principal as the loader.
+    secFlags = nsILoadInfo::SEC_REQUIRE_CORS_DATA_INHERITS |
+               nsILoadInfo::SEC_FORCE_INHERIT_PRINCIPAL;
+  }
+
+  if (mIsAnon) {
+    secFlags |= nsILoadInfo::SEC_COOKIES_OMIT;
+  }
+
+  // Use the responsibleDocument if we have it, except for dedicated workers
+  // where it will be the parent document, which is not the one we want to use.
+  nsresult rv;
+  nsCOMPtr<nsIDocument> responsibleDocument = GetDocumentIfCurrent();
+  if (responsibleDocument && responsibleDocument->NodePrincipal() == mPrincipal) {
+    rv = NS_NewChannel(getter_AddRefs(mChannel),
+                       mRequestURL,
+                       responsibleDocument,
+                       secFlags,
+                       nsIContentPolicy::TYPE_INTERNAL_XMLHTTPREQUEST,
+                       loadGroup,
+                       nullptr,   // aCallbacks
+                       loadFlags);
+  } else {
+    // Otherwise use the principal.
+    rv = NS_NewChannel(getter_AddRefs(mChannel),
+                       mRequestURL,
+                       mPrincipal,
+                       secFlags,
+                       nsIContentPolicy::TYPE_INTERNAL_XMLHTTPREQUEST,
+                       loadGroup,
+                       nullptr,   // aCallbacks
+                       loadFlags);
+  }
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(mChannel));
+  if (httpChannel) {
+    rv = httpChannel->SetRequestMethod(mRequestMethod);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // Set the initiator type
+    nsCOMPtr<nsITimedChannel> timedChannel(do_QueryInterface(httpChannel));
+    if (timedChannel) {
+      timedChannel->SetInitiatorType(NS_LITERAL_STRING("xmlhttprequest"));
+    }
+  }
+
+  // Using the provided principal as the triggeringPrincipal is fine, since we
+  // want to be able to access any of the origins that the principal has access
+  // to during the security checks, but we don't want a document to inherit an
+  // expanded principal, so in that case we need to select the principal in the
+  // expanded principal's whitelist that can load our URL as principalToInherit.
+  nsCOMPtr<nsIPrincipal> resultingDocumentPrincipal(mPrincipal);
+  nsCOMPtr<nsIExpandedPrincipal> ep = do_QueryInterface(mPrincipal);
+  if (ep) {
+    nsTArray<nsCOMPtr<nsIPrincipal>>* whitelist = nullptr;
+    ep->GetWhiteList(&whitelist);
+    if (!whitelist) {
+      return NS_ERROR_FAILURE;
+    }
+    MOZ_ASSERT(!(secFlags & nsILoadInfo::SEC_REQUIRE_SAME_ORIGIN_DATA_INHERITS));
+    bool dataInherits = (secFlags &
+      (nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_DATA_INHERITS |
+       nsILoadInfo::SEC_REQUIRE_CORS_DATA_INHERITS)) != 0;
+    for (const auto& principal : *whitelist) {
+      if (NS_SUCCEEDED(principal->CheckMayLoad(mRequestURL, false, dataInherits))) {
+        resultingDocumentPrincipal = principal;
+        break;
+      }
+    }
+  }
+
+  nsCOMPtr<nsILoadInfo> loadInfo = mChannel->GetLoadInfo();
+  rv = loadInfo->SetPrincipalToInherit(resultingDocumentPrincipal);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  return NS_OK;
+}
+
+nsresult
+XMLHttpRequestMainThread::InitiateFetch(nsIInputStream* aUploadStream,
+                                        int64_t aUploadLength,
+                                        nsACString& aUploadContentType)
+{
+  nsresult rv;
+
+  // nsIRequest::LOAD_BACKGROUND prevents throbber from becoming active, which
+  // in turn keeps STOP button from becoming active.  If the consumer passed in
+  // a progress event handler we must load with nsIRequest::LOAD_NORMAL or
+  // necko won't generate any progress notifications.
+  if (HasListenersFor(nsGkAtoms::onprogress) ||
+      (mUpload && mUpload->HasListenersFor(nsGkAtoms::onprogress))) {
+    nsLoadFlags loadFlags;
+    mChannel->GetLoadFlags(&loadFlags);
+    loadFlags &= ~nsIRequest::LOAD_BACKGROUND;
+    loadFlags |= nsIRequest::LOAD_NORMAL;
+    mChannel->SetLoadFlags(loadFlags);
+  }
+
+  nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(mChannel));
+  if (httpChannel) {
+    // If the user hasn't overridden the Accept header, set it to */* per spec.
+    if (!mAuthorRequestHeaders.Has("accept")) {
+      mAuthorRequestHeaders.Set("accept", NS_LITERAL_CSTRING("*/*"));
+    }
+
+    mAuthorRequestHeaders.ApplyToChannel(httpChannel);
+
+    if (!IsSystemXHR()) {
+      nsCOMPtr<nsPIDOMWindowInner> owner = GetOwner();
+      nsCOMPtr<nsIDocument> doc = owner ? owner->GetExtantDoc() : nullptr;
+      nsContentUtils::SetFetchReferrerURIWithPolicy(mPrincipal, doc,
+                                                    httpChannel,
+                                                    mozilla::net::RP_Default);
+    }
+
+    // Some extensions override the http protocol handler and provide their own
+    // implementation. The channels returned from that implementation don't
+    // always seem to implement the nsIUploadChannel2 interface, presumably
+    // because it's a new interface. Eventually we should remove this and simply
+    // require that http channels implement the new interface (see bug 529041).
+    nsCOMPtr<nsIUploadChannel2> uploadChannel2 = do_QueryInterface(httpChannel);
+    if (!uploadChannel2) {
+      nsCOMPtr<nsIConsoleService> consoleService =
+        do_GetService(NS_CONSOLESERVICE_CONTRACTID);
+      if (consoleService) {
+        consoleService->LogStringMessage(NS_LITERAL_STRING(
+          "Http channel implementation doesn't support nsIUploadChannel2. "
+          "An extension has supplied a non-functional http protocol handler. "
+          "This will break behavior and in future releases not work at all."
+        ).get());
+      }
+    }
+
+    if (aUploadStream) {
+      // If necessary, wrap the stream in a buffered stream so as to guarantee
+      // support for our upload when calling ExplicitSetUploadStream.
+      nsCOMPtr<nsIInputStream> bufferedStream;
+      if (!NS_InputStreamIsBuffered(aUploadStream)) {
+        rv = NS_NewBufferedInputStream(getter_AddRefs(bufferedStream),
+                                       aUploadStream, 4096);
+        NS_ENSURE_SUCCESS(rv, rv);
+
+        aUploadStream = bufferedStream;
+      }
+
+      // We want to use a newer version of the upload channel that won't
+      // ignore the necessary headers for an empty Content-Type.
+      nsCOMPtr<nsIUploadChannel2> uploadChannel2(do_QueryInterface(httpChannel));
+      // This assertion will fire if buggy extensions are installed
+      NS_ASSERTION(uploadChannel2, "http must support nsIUploadChannel2");
+      if (uploadChannel2) {
+          uploadChannel2->ExplicitSetUploadStream(aUploadStream,
+                                                  aUploadContentType,
+                                                  mUploadTotal, mRequestMethod,
+                                                  false);
+      } else {
+        // The http channel doesn't support the new nsIUploadChannel2.
+        // Emulate it as best we can using nsIUploadChannel.
+        if (aUploadContentType.IsEmpty()) {
+          aUploadContentType.AssignLiteral("application/octet-stream");
+        }
+        nsCOMPtr<nsIUploadChannel> uploadChannel =
+          do_QueryInterface(httpChannel);
+        uploadChannel->SetUploadStream(aUploadStream, aUploadContentType,
+                                       mUploadTotal);
+        // Reset the method to its original value
+        httpChannel->SetRequestMethod(mRequestMethod);
+      }
+    }
+  }
+
+  // Due to the chrome-only XHR.channel API, we need a hacky way to set the
+  // SEC_COOKIES_INCLUDE *after* the channel has been has been created, since
+  // .withCredentials can be called after open() is called.
+  // Not doing this for privileged system XHRs since those don't use CORS.
+  if (!IsSystemXHR() && !mIsAnon && mFlagACwithCredentials) {
+    nsCOMPtr<nsILoadInfo> loadInfo = mChannel->GetLoadInfo();
+    static_cast<net::LoadInfo*>(loadInfo.get())->SetIncludeCookiesSecFlag();
+  }
+
+  // Blocking gets are common enough out of XHR that we should mark
+  // the channel slow by default for pipeline purposes
+  AddLoadFlags(mChannel, nsIRequest::INHIBIT_PIPELINE);
+
+  // We never let XHR be blocked by head CSS/JS loads to avoid potential
+  // deadlock where server generation of CSS/JS requires an XHR signal.
+  nsCOMPtr<nsIClassOfService> cos(do_QueryInterface(mChannel));
+  if (cos) {
+    cos->AddClassFlags(nsIClassOfService::Unblocked);
+  }
+
+  // Disable Necko-internal response timeouts.
+  nsCOMPtr<nsIHttpChannelInternal>
+    internalHttpChannel(do_QueryInterface(mChannel));
+  if (internalHttpChannel) {
+    internalHttpChannel->SetResponseTimeoutEnabled(false);
+  }
+
+  if (!mIsAnon) {
+    AddLoadFlags(mChannel, nsIChannel::LOAD_EXPLICIT_CREDENTIALS);
+  }
+
+  // Bypass the network cache in cases where it makes no sense:
+  // POST responses are always unique, and we provide no API that would
+  // allow our consumers to specify a "cache key" to access old POST
+  // responses, so they are not worth caching.
+  if (mRequestMethod.EqualsLiteral("POST")) {
+    AddLoadFlags(mChannel,
+                 nsICachingChannel::LOAD_BYPASS_LOCAL_CACHE |
+                 nsIRequest::INHIBIT_CACHING);
+  } else {
+    // When we are sync loading, we need to bypass the local cache when it would
+    // otherwise block us waiting for exclusive access to the cache.  If we don't
+    // do this, then we could dead lock in some cases (see bug 309424).
+    //
+    // Also don't block on the cache entry on async if it is busy - favoring parallelism
+    // over cache hit rate for xhr. This does not disable the cache everywhere -
+    // only in cases where more than one channel for the same URI is accessed
+    // simultanously.
+    AddLoadFlags(mChannel, nsICachingChannel::LOAD_BYPASS_LOCAL_CACHE_IF_BUSY);
+  }
+
+  // Since we expect XML data, set the type hint accordingly
+  // if the channel doesn't know any content type.
+  // This means that we always try to parse local files as XML
+  // ignoring return value, as this is not critical
+  nsAutoCString contentType;
+  if (NS_FAILED(mChannel->GetContentType(contentType)) ||
+      contentType.IsEmpty() ||
+      contentType.Equals(UNKNOWN_CONTENT_TYPE)) {
+    mChannel->SetContentType(NS_LITERAL_CSTRING("application/xml"));
+  }
+
+  // Set up the preflight if needed
+  if (!IsSystemXHR()) {
+    nsTArray<nsCString> CORSUnsafeHeaders;
+    mAuthorRequestHeaders.GetCORSUnsafeHeaders(CORSUnsafeHeaders);
+    nsCOMPtr<nsILoadInfo> loadInfo = mChannel->GetLoadInfo();
+    loadInfo->SetCorsPreflightInfo(CORSUnsafeHeaders,
+                                   mFlagHadUploadListenersOnSend);
+  }
+
+  // Hook us up to listen to redirects and the like. Only do this very late
+  // since this creates a cycle between the channel and us. This cycle has
+  // to be manually broken if anything below fails.
+  mChannel->GetNotificationCallbacks(getter_AddRefs(mNotificationCallbacks));
+  mChannel->SetNotificationCallbacks(this);
+
+  if (internalHttpChannel) {
+    internalHttpChannel->SetBlockAuthPrompt(ShouldBlockAuthPrompt());
+  }
+
+  // Because of bug 682305, we can't let listener be the XHR object itself
+  // because JS wouldn't be able to use it. So create a listener around 'this'.
+  // Make sure to hold a strong reference so that we don't leak the wrapper.
+  nsCOMPtr<nsIStreamListener> listener = new net::nsStreamListenerWrapper(this);
+
+  // Start reading from the channel
+  rv = mChannel->AsyncOpen2(listener);
+  listener = nullptr;
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    // Drop our ref to the channel to avoid cycles. Also drop channel's
+    // ref to us to be extra safe.
+    mChannel->SetNotificationCallbacks(mNotificationCallbacks);
+    mChannel = nullptr;
+
+    mErrorLoad = true;
+
+    // Per spec, we throw on sync errors, but not async.
+    if (mFlagSynchronous) {
+      return NS_ERROR_DOM_NETWORK_ERR;
+    }
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::Send(nsIVariant* aVariant)
+{
+  if (!aVariant) {
+    return SendInternal(nullptr);
+  }
+
+  uint16_t dataType;
+  nsresult rv = aVariant->GetDataType(&dataType);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (dataType == nsIDataType::VTYPE_INTERFACE ||
+      dataType == nsIDataType::VTYPE_INTERFACE_IS) {
+    nsCOMPtr<nsISupports> supports;
+    nsID *iid;
+    rv = aVariant->GetAsInterface(&iid, getter_AddRefs(supports));
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    free(iid);
+
+    // document?
+    nsCOMPtr<nsIDocument> doc = do_QueryInterface(supports);
+    if (doc) {
+      RequestBody<nsIDocument> body(doc);
+      return SendInternal(&body);
+    }
+
+    // nsISupportsString?
+    nsCOMPtr<nsISupportsString> wstr = do_QueryInterface(supports);
+    if (wstr) {
+      nsAutoString string;
+      wstr->GetData(string);
+      RequestBody<const nsAString> body(&string);
+      return SendInternal(&body);
+    }
+
+    // nsIInputStream?
+    nsCOMPtr<nsIInputStream> stream = do_QueryInterface(supports);
+    if (stream) {
+      RequestBody<nsIInputStream> body(stream);
+      return SendInternal(&body);
+    }
+
+    // nsIXHRSendable?
+    nsCOMPtr<nsIXHRSendable> sendable = do_QueryInterface(supports);
+    if (sendable) {
+      RequestBody<nsIXHRSendable> body(sendable);
+      return SendInternal(&body);
+    }
+
+    // ArrayBuffer?
+    JS::RootingContext* rootingCx = RootingCx();
+    JS::Rooted<JS::Value> realVal(rootingCx);
+
+    nsresult rv = aVariant->GetAsJSVal(&realVal);
+    if (NS_SUCCEEDED(rv) && !realVal.isPrimitive()) {
+      JS::Rooted<JSObject*> obj(rootingCx, realVal.toObjectOrNull());
+      RootedTypedArray<ArrayBuffer> buf(rootingCx);
+      if (buf.Init(obj)) {
+        RequestBody<const ArrayBuffer> body(&buf);
+        return SendInternal(&body);
+      }
+    }
+  } else if (dataType == nsIDataType::VTYPE_VOID ||
+           dataType == nsIDataType::VTYPE_EMPTY) {
+    return SendInternal(nullptr);
+  }
+
+  char16_t* data = nullptr;
+  uint32_t len = 0;
+  rv = aVariant->GetAsWStringWithSize(&len, &data);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsString string;
+  string.Adopt(data, len);
+
+  RequestBody<const nsAString> body(&string);
+  return SendInternal(&body);
+}
+
+nsresult
+XMLHttpRequestMainThread::SendInternal(const RequestBodyBase* aBody)
+{
+  NS_ENSURE_TRUE(mPrincipal, NS_ERROR_NOT_INITIALIZED);
+
+  // Step 1
+  if (mState != State::opened) {
+    return NS_ERROR_DOM_INVALID_STATE_XHR_MUST_BE_OPENED;
+  }
+
+  // Step 2
+  if (mFlagSend) {
+    return NS_ERROR_DOM_INVALID_STATE_XHR_MUST_NOT_BE_SENDING;
+  }
+
+  nsresult rv = CheckInnerWindowCorrectness();
+  if (NS_FAILED(rv)) {
+    return NS_ERROR_DOM_INVALID_STATE_XHR_HAS_INVALID_CONTEXT;
+  }
+
+  // If open() failed to create the channel, then throw a network error
+  // as per spec. We really should create the channel here in send(), but
+  // we have internal code relying on the channel being created in open().
+  if (!mChannel) {
+    return NS_ERROR_DOM_NETWORK_ERR;
+  }
+
+  PopulateNetworkInterfaceId();
+
+  // XXX We should probably send a warning to the JS console
+  //     if there are no event listeners set and we are doing
+  //     an asynchronous call.
+
+  mUploadTransferred = 0;
+  mUploadTotal = 0;
+  // By default we don't have any upload, so mark upload complete.
+  mUploadComplete = true;
+  mErrorLoad = false;
+  mLoadTotal = -1;
+  nsCOMPtr<nsIInputStream> uploadStream;
+  nsAutoCString uploadContentType;
+  nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(mChannel));
+  if (aBody && httpChannel &&
+      !mRequestMethod.EqualsLiteral("GET") &&
+      !mRequestMethod.EqualsLiteral("HEAD")) {
+
+    nsAutoCString charset;
+    nsAutoCString defaultContentType;
+    uint64_t size_u64;
+    rv = aBody->GetAsStream(getter_AddRefs(uploadStream),
+                            &size_u64, defaultContentType, charset);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // make sure it fits within js MAX_SAFE_INTEGER
+    mUploadTotal =
+      net::InScriptableRange(size_u64) ? static_cast<int64_t>(size_u64) : -1;
+
+    if (uploadStream) {
+      // If author set no Content-Type, use the default from GetAsStream().
+      mAuthorRequestHeaders.Get("content-type", uploadContentType);
+      if (uploadContentType.IsVoid()) {
+        uploadContentType = defaultContentType;
+
+        if (!charset.IsEmpty()) {
+          // If we are providing the default content type, then we also need to
+          // provide a charset declaration.
+          uploadContentType.Append(NS_LITERAL_CSTRING(";charset="));
+          uploadContentType.Append(charset);
+        }
+      }
+
+      // We don't want to set a charset for streams.
+      if (!charset.IsEmpty()) {
+        // Replace all case-insensitive matches of the charset in the
+        // content-type with the correct case.
+        RequestHeaders::CharsetIterator iter(uploadContentType);
+        const nsCaseInsensitiveCStringComparator cmp;
+        while (iter.Next()) {
+          if (!iter.Equals(charset, cmp)) {
+            iter.Replace(charset);
+          }
+        }
+      }
+
+      mUploadComplete = false;
+    }
+  }
+
+  ResetResponse();
+
+  // Check if we should enable cross-origin upload listeners.
+  if (mUpload && mUpload->HasListeners()) {
+    mFlagHadUploadListenersOnSend = true;
+  }
+
+  mIsMappedArrayBuffer = false;
+  if (mResponseType == XMLHttpRequestResponseType::Arraybuffer &&
+      Preferences::GetBool("dom.mapped_arraybuffer.enabled", true)) {
+    nsCOMPtr<nsIURI> uri;
+    nsAutoCString scheme;
+
+    rv = mChannel->GetURI(getter_AddRefs(uri));
+    if (NS_SUCCEEDED(rv)) {
+      uri->GetScheme(scheme);
+      if (scheme.LowerCaseEqualsLiteral("jar")) {
+        mIsMappedArrayBuffer = true;
+      }
+    }
+  }
+
+  rv = InitiateFetch(uploadStream, mUploadTotal, uploadContentType);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Start our timeout
+  mRequestSentTime = PR_Now();
+  StartTimeoutTimer();
+
+  mWaitingForOnStopRequest = true;
+
+  // Step 8
+  mFlagSend = true;
+
+  // If we're synchronous, spin an event loop here and wait
+  if (mFlagSynchronous) {
+    mFlagSyncLooping = true;
+
+    nsCOMPtr<nsIDocument> suspendedDoc;
+    nsCOMPtr<nsIRunnable> resumeTimeoutRunnable;
+    if (GetOwner()) {
+      if (nsCOMPtr<nsPIDOMWindowOuter> topWindow = GetOwner()->GetOuterWindow()->GetTop()) {
+        if (nsCOMPtr<nsPIDOMWindowInner> topInner = topWindow->GetCurrentInnerWindow()) {
+          suspendedDoc = topWindow->GetExtantDoc();
+          if (suspendedDoc) {
+            suspendedDoc->SuppressEventHandling(nsIDocument::eEvents);
+          }
+          topInner->Suspend();
+          resumeTimeoutRunnable = new nsResumeTimeoutsEvent(topInner);
+        }
+      }
+    }
+
+    StopProgressEventTimer();
+
+    SyncTimeoutType syncTimeoutType = MaybeStartSyncTimeoutTimer();
+    if (syncTimeoutType == eErrorOrExpired) {
+      Abort();
+      rv = NS_ERROR_DOM_NETWORK_ERR;
+    }
+
+    if (NS_SUCCEEDED(rv)) {
+      nsAutoSyncOperation sync(suspendedDoc);
+      nsIThread *thread = NS_GetCurrentThread();
+      while (mFlagSyncLooping) {
+        if (!NS_ProcessNextEvent(thread)) {
+          rv = NS_ERROR_UNEXPECTED;
+          break;
+        }
+      }
+
+      // Time expired... We should throw.
+      if (syncTimeoutType == eTimerStarted && !mSyncTimeoutTimer) {
+        rv = NS_ERROR_DOM_NETWORK_ERR;
+      }
+
+      CancelSyncTimeoutTimer();
+    }
+
+    if (suspendedDoc) {
+      suspendedDoc->UnsuppressEventHandlingAndFireEvents(nsIDocument::eEvents,
+                                                         true);
+    }
+
+    if (resumeTimeoutRunnable) {
+      NS_DispatchToCurrentThread(resumeTimeoutRunnable);
+    }
+  } else {
+    // Now that we've successfully opened the channel, we can change state.  Note
+    // that this needs to come after the AsyncOpen() and rv check, because this
+    // can run script that would try to restart this request, and that could end
+    // up doing our AsyncOpen on a null channel if the reentered AsyncOpen fails.
+    StopProgressEventTimer();
+
+    // Upload phase beginning; start the progress event timer if necessary.
+    if (mUpload && mUpload->HasListenersFor(nsGkAtoms::onprogress)) {
+      StartProgressEventTimer();
+    }
+    // Dispatch loadstart events
+    DispatchProgressEvent(this, ProgressEventType::loadstart, 0, -1);
+    if (mUpload && !mUploadComplete) {
+      DispatchProgressEvent(mUpload, ProgressEventType::loadstart,
+                            0, mUploadTotal);
+    }
+  }
+
+  if (!mChannel) {
+    // Per spec, silently fail on async request failures; throw for sync.
+    if (mFlagSynchronous) {
+      return NS_ERROR_DOM_NETWORK_ERR;
+    } else {
+      // Defer the actual sending of async events just in case listeners
+      // are attached after the send() method is called.
+      NS_DispatchToCurrentThread(
+        NewRunnableMethod<ProgressEventType>(this,
+          &XMLHttpRequestMainThread::CloseRequestWithError,
+          ProgressEventType::error));
+      return NS_OK;
+    }
+  }
+
+  return rv;
+}
+
+// http://dvcs.w3.org/hg/xhr/raw-file/tip/Overview.html#dom-xmlhttprequest-setrequestheader
+NS_IMETHODIMP
+XMLHttpRequestMainThread::SetRequestHeader(const nsACString& aName,
+                                           const nsACString& aValue)
+{
+  // Step 1
+  if (mState != State::opened) {
+    return NS_ERROR_DOM_INVALID_STATE_XHR_MUST_BE_OPENED;
+  }
+
+  // Step 2
+  if (mFlagSend) {
+    return NS_ERROR_DOM_INVALID_STATE_XHR_MUST_NOT_BE_SENDING;
+  }
+
+  // Step 3
+  nsAutoCString value(aValue);
+  static const char kHTTPWhitespace[] = "\n\t\r ";
+  value.Trim(kHTTPWhitespace);
+
+  // Step 4
+  if (!NS_IsValidHTTPToken(aName) || !NS_IsReasonableHTTPHeaderValue(value)) {
+    return NS_ERROR_DOM_INVALID_HEADER_NAME;
+  }
+
+  // Step 5
+  bool isPrivilegedCaller = IsSystemXHR();
+  bool isForbiddenHeader = nsContentUtils::IsForbiddenRequestHeader(aName);
+  if (!isPrivilegedCaller && isForbiddenHeader) {
+    NS_ConvertUTF8toUTF16 name(aName);
+    const char16_t* params[] = { name.get() };
+    LogMessage("ForbiddenHeaderWarning", GetOwner(), params, ArrayLength(params));
+    return NS_OK;
+  }
+
+  // Step 6.1
+  // Skipping for now, as normalizing the case of header names may not be
+  // web-compatible. See bug 1285036.
+
+  // Step 6.2-6.3
+  // Gecko-specific: invalid headers can be set by privileged
+  //                 callers, but will not merge.
+  if (isPrivilegedCaller && isForbiddenHeader) {
+    mAuthorRequestHeaders.Set(aName, value);
+  } else {
+    mAuthorRequestHeaders.MergeOrSet(aName, value);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetTimeout(uint32_t *aTimeout)
+{
+  *aTimeout = Timeout();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::SetTimeout(uint32_t aTimeout)
+{
+  ErrorResult rv;
+  SetTimeout(aTimeout, rv);
+  return rv.StealNSResult();
+}
+
+void
+XMLHttpRequestMainThread::SetTimeout(uint32_t aTimeout, ErrorResult& aRv)
+{
+  if (mFlagSynchronous && mState != State::unsent && HasOrHasHadOwner()) {
+    /* Timeout is not supported for synchronous requests with an owning window,
+       per XHR2 spec. */
+    LogMessage("TimeoutSyncXHRWarning", GetOwner());
+    aRv.Throw(NS_ERROR_DOM_INVALID_ACCESS_XHR_TIMEOUT_AND_RESPONSETYPE_UNSUPPORTED_FOR_SYNC);
+    return;
+  }
+
+  mTimeoutMilliseconds = aTimeout;
+  if (mRequestSentTime) {
+    StartTimeoutTimer();
+  }
+}
+
+void
+XMLHttpRequestMainThread::StartTimeoutTimer()
+{
+  MOZ_ASSERT(mRequestSentTime,
+             "StartTimeoutTimer mustn't be called before the request was sent!");
+  if (mState == State::done) {
+    // do nothing!
+    return;
+  }
+
+  if (mTimeoutTimer) {
+    mTimeoutTimer->Cancel();
+  }
+
+  if (!mTimeoutMilliseconds) {
+    return;
+  }
+
+  if (!mTimeoutTimer) {
+    mTimeoutTimer = do_CreateInstance(NS_TIMER_CONTRACTID);
+  }
+  uint32_t elapsed =
+    (uint32_t)((PR_Now() - mRequestSentTime) / PR_USEC_PER_MSEC);
+  mTimeoutTimer->InitWithCallback(
+    this,
+    mTimeoutMilliseconds > elapsed ? mTimeoutMilliseconds - elapsed : 0,
+    nsITimer::TYPE_ONE_SHOT
+  );
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetReadyState(uint16_t *aState)
+{
+  *aState = ReadyState();
+  return NS_OK;
+}
+
+uint16_t
+XMLHttpRequestMainThread::ReadyState() const
+{
+  // Translate some of our internal states for external consumers
+  switch(mState) {
+    case State::unsent:
+      return UNSENT;
+    case State::opened:
+      return OPENED;
+    case State::headers_received:
+      return HEADERS_RECEIVED;
+    case State::loading:
+      return LOADING;
+    case State::done:
+      return DONE;
+    default:
+      MOZ_CRASH("Unknown state");
+  }
+  return 0;
+}
+
+void XMLHttpRequestMainThread::OverrideMimeType(const nsAString& aMimeType, ErrorResult& aRv)
+{
+  if (mState == State::loading || mState == State::done) {
+    ResetResponse();
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_XHR_MUST_NOT_BE_LOADING_OR_DONE);
+    return;
+  }
+
+  mOverrideMimeType = aMimeType;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::SlowOverrideMimeType(const nsAString& aMimeType)
+{
+  ErrorResult aRv;
+  OverrideMimeType(aMimeType, aRv);
+  return aRv.StealNSResult();
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetMozBackgroundRequest(bool *_retval)
+{
+  *_retval = MozBackgroundRequest();
+  return NS_OK;
+}
+
+bool
+XMLHttpRequestMainThread::MozBackgroundRequest() const
+{
+  return mFlagBackgroundRequest;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::SetMozBackgroundRequest(bool aMozBackgroundRequest)
+{
+  if (!IsSystemXHR()) {
+    return NS_ERROR_DOM_SECURITY_ERR;
+  }
+
+  if (mState != State::unsent) {
+    // Can't change this while we're in the middle of something.
+    return NS_ERROR_DOM_INVALID_STATE_XHR_MUST_NOT_BE_SENDING;
+  }
+
+  mFlagBackgroundRequest = aMozBackgroundRequest;
+
+  return NS_OK;
+}
+
+void
+XMLHttpRequestMainThread::SetMozBackgroundRequest(bool aMozBackgroundRequest,
+                                                  ErrorResult& aRv)
+{
+  // No errors for this webIDL method on main-thread.
+  SetMozBackgroundRequest(aMozBackgroundRequest);
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetWithCredentials(bool *_retval)
+{
+  *_retval = WithCredentials();
+  return NS_OK;
+}
+
+bool
+XMLHttpRequestMainThread::WithCredentials() const
+{
+  return mFlagACwithCredentials;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::SetWithCredentials(bool aWithCredentials)
+{
+  ErrorResult rv;
+  SetWithCredentials(aWithCredentials, rv);
+  return rv.StealNSResult();
+}
+
+void
+XMLHttpRequestMainThread::SetWithCredentials(bool aWithCredentials, ErrorResult& aRv)
+{
+  // Return error if we're already processing a request.  Note that we can't use
+  // ReadyState() here, because it can't differentiate between "opened" and
+  // "sent", so we use mState directly.
+
+  if ((mState != State::unsent && mState != State::opened) ||
+      mFlagSend || mIsAnon) {
+    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_XHR_MUST_NOT_BE_SENDING);
+    return;
+  }
+
+  mFlagACwithCredentials = aWithCredentials;
+}
+
+nsresult
+XMLHttpRequestMainThread::ChangeState(State aState, bool aBroadcast)
+{
+  mState = aState;
+  nsresult rv = NS_OK;
+
+  if (aState != State::headers_received && aState != State::loading) {
+    StopProgressEventTimer();
+  }
+
+
+  if (aBroadcast && (!mFlagSynchronous ||
+                     aState == State::opened ||
+                     aState == State::done)) {
+    rv = FireReadystatechangeEvent();
+  }
+
+  return rv;
+}
+
+/////////////////////////////////////////////////////
+// nsIChannelEventSink methods:
+//
+NS_IMETHODIMP
+XMLHttpRequestMainThread::AsyncOnChannelRedirect(nsIChannel *aOldChannel,
+                                                 nsIChannel *aNewChannel,
+                                                 uint32_t    aFlags,
+                                                 nsIAsyncVerifyRedirectCallback *callback)
+{
+  NS_PRECONDITION(aNewChannel, "Redirect without a channel?");
+
+  // Prepare to receive callback
+  mRedirectCallback = callback;
+  mNewRedirectChannel = aNewChannel;
+
+  if (mChannelEventSink) {
+    nsCOMPtr<nsIAsyncVerifyRedirectCallback> fwd =
+      EnsureXPCOMifier();
+
+    nsresult rv = mChannelEventSink->AsyncOnChannelRedirect(aOldChannel,
+                                                            aNewChannel,
+                                                            aFlags, fwd);
+    if (NS_FAILED(rv)) {
+        mRedirectCallback = nullptr;
+        mNewRedirectChannel = nullptr;
+    }
+    return rv;
+  }
+  OnRedirectVerifyCallback(NS_OK);
+  return NS_OK;
+}
+
+nsresult
+XMLHttpRequestMainThread::OnRedirectVerifyCallback(nsresult result)
+{
+  NS_ASSERTION(mRedirectCallback, "mRedirectCallback not set in callback");
+  NS_ASSERTION(mNewRedirectChannel, "mNewRedirectChannel not set in callback");
+
+  if (NS_SUCCEEDED(result)) {
+    mChannel = mNewRedirectChannel;
+
+    nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(mChannel));
+    if (httpChannel) {
+      // Ensure all original headers are duplicated for the new channel (bug #553888)
+      mAuthorRequestHeaders.ApplyToChannel(httpChannel);
+    }
+  } else {
+    mErrorLoad = true;
+  }
+
+  mNewRedirectChannel = nullptr;
+
+  mRedirectCallback->OnRedirectVerifyCallback(result);
+  mRedirectCallback = nullptr;
+
+  // It's important that we return success here. If we return the result code
+  // that we were passed, JavaScript callers who cancel the redirect will wind
+  // up throwing an exception in the process.
+  return NS_OK;
+}
+
+/////////////////////////////////////////////////////
+// nsIProgressEventSink methods:
+//
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::OnProgress(nsIRequest *aRequest, nsISupports *aContext, int64_t aProgress, int64_t aProgressMax)
+{
+  // When uploading, OnProgress reports also headers in aProgress and aProgressMax.
+  // So, try to remove the headers, if possible.
+  bool lengthComputable = (aProgressMax != -1);
+  if (InUploadPhase()) {
+    int64_t loaded = aProgress;
+    if (lengthComputable) {
+      int64_t headerSize = aProgressMax - mUploadTotal;
+      loaded -= headerSize;
+    }
+    mUploadTransferred = loaded;
+    mProgressSinceLastProgressEvent = true;
+
+    if (!mFlagSynchronous && !mProgressTimerIsActive) {
+      StartProgressEventTimer();
+    }
+  } else {
+    mLoadTotal = aProgressMax;
+    mLoadTransferred = aProgress;
+    // OnDataAvailable() handles mProgressSinceLastProgressEvent
+    // for the download phase.
+  }
+
+  if (mProgressEventSink) {
+    mProgressEventSink->OnProgress(aRequest, aContext, aProgress,
+                                   aProgressMax);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::OnStatus(nsIRequest *aRequest, nsISupports *aContext, nsresult aStatus, const char16_t *aStatusArg)
+{
+  if (mProgressEventSink) {
+    mProgressEventSink->OnStatus(aRequest, aContext, aStatus, aStatusArg);
+  }
+
+  return NS_OK;
+}
+
+bool
+XMLHttpRequestMainThread::AllowUploadProgress()
+{
+  return !IsCrossSiteCORSRequest() ||
+         mFlagHadUploadListenersOnSend;
+}
+
+/////////////////////////////////////////////////////
+// nsIInterfaceRequestor methods:
+//
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetInterface(const nsIID & aIID, void **aResult)
+{
+  nsresult rv;
+
+  // Make sure to return ourselves for the channel event sink interface and
+  // progress event sink interface, no matter what.  We can forward these to
+  // mNotificationCallbacks if it wants to get notifications for them.  But we
+  // need to see these notifications for proper functioning.
+  if (aIID.Equals(NS_GET_IID(nsIChannelEventSink))) {
+    mChannelEventSink = do_GetInterface(mNotificationCallbacks);
+    *aResult = static_cast<nsIChannelEventSink*>(EnsureXPCOMifier().take());
+    return NS_OK;
+  } else if (aIID.Equals(NS_GET_IID(nsIProgressEventSink))) {
+    mProgressEventSink = do_GetInterface(mNotificationCallbacks);
+    *aResult = static_cast<nsIProgressEventSink*>(EnsureXPCOMifier().take());
+    return NS_OK;
+  }
+
+  // Now give mNotificationCallbacks (if non-null) a chance to return the
+  // desired interface.
+  if (mNotificationCallbacks) {
+    rv = mNotificationCallbacks->GetInterface(aIID, aResult);
+    if (NS_SUCCEEDED(rv)) {
+      NS_ASSERTION(*aResult, "Lying nsIInterfaceRequestor implementation!");
+      return rv;
+    }
+  }
+
+  if (mFlagBackgroundRequest) {
+    nsCOMPtr<nsIInterfaceRequestor> badCertHandler(do_CreateInstance(NS_BADCERTHANDLER_CONTRACTID, &rv));
+
+    // Ignore failure to get component, we may not have all its dependencies
+    // available
+    if (NS_SUCCEEDED(rv)) {
+      rv = badCertHandler->GetInterface(aIID, aResult);
+      if (NS_SUCCEEDED(rv))
+        return rv;
+    }
+  }
+  else if (aIID.Equals(NS_GET_IID(nsIAuthPrompt)) ||
+           aIID.Equals(NS_GET_IID(nsIAuthPrompt2))) {
+    nsCOMPtr<nsIPromptFactory> wwatch =
+      do_GetService(NS_WINDOWWATCHER_CONTRACTID, &rv);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    // Get the an auth prompter for our window so that the parenting
+    // of the dialogs works as it should when using tabs.
+
+    nsCOMPtr<nsPIDOMWindowOuter> window;
+    if (GetOwner()) {
+      window = GetOwner()->GetOuterWindow();
+    }
+
+    return wwatch->GetPrompt(window, aIID,
+                             reinterpret_cast<void**>(aResult));
+  }
+  // Now check for the various XHR non-DOM interfaces, except
+  // nsIProgressEventSink and nsIChannelEventSink which we already
+  // handled above.
+  else if (aIID.Equals(NS_GET_IID(nsIStreamListener))) {
+    *aResult = static_cast<nsIStreamListener*>(EnsureXPCOMifier().take());
+    return NS_OK;
+  }
+  else if (aIID.Equals(NS_GET_IID(nsIRequestObserver))) {
+    *aResult = static_cast<nsIRequestObserver*>(EnsureXPCOMifier().take());
+    return NS_OK;
+  }
+  else if (aIID.Equals(NS_GET_IID(nsITimerCallback))) {
+    *aResult = static_cast<nsITimerCallback*>(EnsureXPCOMifier().take());
+    return NS_OK;
+  }
+
+  return QueryInterface(aIID, aResult);
+}
+
+void
+XMLHttpRequestMainThread::GetInterface(JSContext* aCx, nsIJSID* aIID,
+                                       JS::MutableHandle<JS::Value> aRetval,
+                                       ErrorResult& aRv)
+{
+  dom::GetInterface(aCx, this, aIID, aRetval, aRv);
+}
+
+XMLHttpRequestUpload*
+XMLHttpRequestMainThread::GetUpload(ErrorResult& aRv)
+{
+  if (!mUpload) {
+    mUpload = new XMLHttpRequestUpload(this);
+  }
+  return mUpload;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetUpload(nsIXMLHttpRequestUpload** aUpload)
+{
+  ErrorResult rv;
+  RefPtr<XMLHttpRequestUpload> upload = GetUpload(rv);
+  upload.forget(aUpload);
+  return rv.StealNSResult();
+}
+
+bool
+XMLHttpRequestMainThread::MozAnon() const
+{
+  return mIsAnon;
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetMozAnon(bool* aAnon)
+{
+  *aAnon = MozAnon();
+  return NS_OK;
+}
+
+bool
+XMLHttpRequestMainThread::MozSystem() const
+{
+  return IsSystemXHR();
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::GetMozSystem(bool* aSystem)
+{
+  *aSystem = MozSystem();
+  return NS_OK;
+}
+
+void
+XMLHttpRequestMainThread::HandleTimeoutCallback()
+{
+  if (mState == State::done) {
+    NS_NOTREACHED("XMLHttpRequestMainThread::HandleTimeoutCallback with completed request");
+    // do nothing!
+    return;
+  }
+
+  mFlagTimedOut = true;
+  CloseRequestWithError(ProgressEventType::timeout);
+}
+
+NS_IMETHODIMP
+XMLHttpRequestMainThread::Notify(nsITimer* aTimer)
+{
+  if (mProgressNotifier == aTimer) {
+    HandleProgressTimerCallback();
+    return NS_OK;
+  }
+
+  if (mTimeoutTimer == aTimer) {
+    HandleTimeoutCallback();
+    return NS_OK;
+  }
+
+  if (mSyncTimeoutTimer == aTimer) {
+    HandleSyncTimeoutTimer();
+    return NS_OK;
+  }
+
+  // Just in case some JS user wants to QI to nsITimerCallback and play with us...
+  NS_WARNING("Unexpected timer!");
+  return NS_ERROR_INVALID_POINTER;
+}
+
+void
+XMLHttpRequestMainThread::HandleProgressTimerCallback()
+{
+  // Don't fire the progress event if mLoadTotal is 0, see XHR spec step 6.1
+  if (!mLoadTotal && mLoadTransferred) {
+    return;
+  }
+
+  mProgressTimerIsActive = false;
+
+  if (!mProgressSinceLastProgressEvent || mErrorLoad) {
+    return;
+  }
+
+  if (InUploadPhase()) {
+    if (mUpload && !mUploadComplete) {
+      DispatchProgressEvent(mUpload, ProgressEventType::progress,
+                            mUploadTransferred, mUploadTotal);
+    }
+  } else {
+    FireReadystatechangeEvent();
+    DispatchProgressEvent(this, ProgressEventType::progress,
+                          mLoadTransferred, mLoadTotal);
+  }
+
+  mProgressSinceLastProgressEvent = false;
+
+  StartProgressEventTimer();
+}
+
+void
+XMLHttpRequestMainThread::StopProgressEventTimer()
+{
+  if (mProgressNotifier) {
+    mProgressTimerIsActive = false;
+    mProgressNotifier->Cancel();
+  }
+}
+
+void
+XMLHttpRequestMainThread::StartProgressEventTimer()
+{
+  if (!mProgressNotifier) {
+    mProgressNotifier = do_CreateInstance(NS_TIMER_CONTRACTID);
+  }
+  if (mProgressNotifier) {
+    mProgressTimerIsActive = true;
+    mProgressNotifier->Cancel();
+    mProgressNotifier->InitWithCallback(this, NS_PROGRESS_EVENT_INTERVAL,
+                                        nsITimer::TYPE_ONE_SHOT);
+  }
+}
+
+XMLHttpRequestMainThread::SyncTimeoutType
+XMLHttpRequestMainThread::MaybeStartSyncTimeoutTimer()
+{
+  MOZ_ASSERT(mFlagSynchronous);
+
+  nsIDocument* doc = GetDocumentIfCurrent();
+  if (!doc || !doc->GetPageUnloadingEventTimeStamp()) {
+    return eNoTimerNeeded;
+  }
+
+  // If we are in a beforeunload or a unload event, we must force a timeout.
+  TimeDuration diff = (TimeStamp::NowLoRes() - doc->GetPageUnloadingEventTimeStamp());
+  if (diff.ToMilliseconds() > MAX_SYNC_TIMEOUT_WHEN_UNLOADING) {
+    return eErrorOrExpired;
+  }
+
+  mSyncTimeoutTimer = do_CreateInstance(NS_TIMER_CONTRACTID);
+  if (!mSyncTimeoutTimer) {
+    return eErrorOrExpired;
+  }
+
+  uint32_t timeout = MAX_SYNC_TIMEOUT_WHEN_UNLOADING - diff.ToMilliseconds();
+  nsresult rv = mSyncTimeoutTimer->InitWithCallback(this, timeout,
+                                                    nsITimer::TYPE_ONE_SHOT);
+  return NS_FAILED(rv) ? eErrorOrExpired : eTimerStarted;
+}
+
+void
+XMLHttpRequestMainThread::HandleSyncTimeoutTimer()
+{
+  MOZ_ASSERT(mSyncTimeoutTimer);
+  MOZ_ASSERT(mFlagSyncLooping);
+
+  CancelSyncTimeoutTimer();
+  Abort();
+}
+
+void
+XMLHttpRequestMainThread::CancelSyncTimeoutTimer()
+{
+  if (mSyncTimeoutTimer) {
+    mSyncTimeoutTimer->Cancel();
+    mSyncTimeoutTimer = nullptr;
+  }
+}
+
+already_AddRefed<nsXMLHttpRequestXPCOMifier>
+XMLHttpRequestMainThread::EnsureXPCOMifier()
+{
+  if (!mXPCOMifier) {
+    mXPCOMifier = new nsXMLHttpRequestXPCOMifier(this);
+  }
+  RefPtr<nsXMLHttpRequestXPCOMifier> newRef(mXPCOMifier);
+  return newRef.forget();
+}
+
+bool
+XMLHttpRequestMainThread::ShouldBlockAuthPrompt()
+{
+  // Verify that it's ok to prompt for credentials here, per spec
+  // http://xhr.spec.whatwg.org/#the-send%28%29-method
+
+  if (mAuthorRequestHeaders.Has("authorization")) {
+    return true;
+  }
+
+  nsCOMPtr<nsIURI> uri;
+  nsresult rv = mChannel->GetURI(getter_AddRefs(uri));
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+
+  // Also skip if a username and/or password is provided in the URI.
+  nsCString username;
+  rv = uri->GetUsername(username);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+
+  nsCString password;
+  rv = uri->GetPassword(password);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return false;
+  }
+
+  if (!username.IsEmpty() || !password.IsEmpty()) {
+    return true;
+  }
+
+  return false;
+}
+
+void
+XMLHttpRequestMainThread::TruncateResponseText()
+{
+  mResponseText.Truncate();
+  XMLHttpRequestBinding::ClearCachedResponseTextValue(this);
+}
+
+NS_IMPL_ISUPPORTS(XMLHttpRequestMainThread::nsHeaderVisitor, nsIHttpHeaderVisitor)
+
+NS_IMETHODIMP XMLHttpRequestMainThread::
+nsHeaderVisitor::VisitHeader(const nsACString &header, const nsACString &value)
+{
+  if (mXHR.IsSafeHeader(header, mHttpChannel)) {
+    mHeaders.Append(header);
+    mHeaders.AppendLiteral(": ");
+    mHeaders.Append(value);
+    mHeaders.AppendLiteral("\r\n");
+  }
+  return NS_OK;
+}
+
+void
+XMLHttpRequestMainThread::MaybeCreateBlobStorage()
+{
+  MOZ_ASSERT(mResponseType == XMLHttpRequestResponseType::Blob);
+
+  if (mBlobStorage) {
+    return;
+  }
+
+  MutableBlobStorage::MutableBlobStorageType storageType =
+    BasePrincipal::Cast(mPrincipal)->PrivateBrowsingId() == 0
+      ? MutableBlobStorage::eCouldBeInTemporaryFile
+      : MutableBlobStorage::eOnlyInMemory;
+
+  mBlobStorage = new MutableBlobStorage(storageType);
+}
+
+void
+XMLHttpRequestMainThread::BlobStoreCompleted(MutableBlobStorage* aBlobStorage,
+                                             Blob* aBlob, nsresult aRv)
+{
+  // Ok, the state is changed...
+  if (mBlobStorage != aBlobStorage || NS_FAILED(aRv)) {
+    return;
+  }
+
+  MOZ_ASSERT(mState != State::done);
+
+  mResponseBlob = aBlob;
+  mBlobStorage = nullptr;
+
+  ChangeStateToDone();
+}
+
+// nsXMLHttpRequestXPCOMifier implementation
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsXMLHttpRequestXPCOMifier)
+  NS_INTERFACE_MAP_ENTRY(nsIStreamListener)
+  NS_INTERFACE_MAP_ENTRY(nsIRequestObserver)
+  NS_INTERFACE_MAP_ENTRY(nsIChannelEventSink)
+  NS_INTERFACE_MAP_ENTRY(nsIAsyncVerifyRedirectCallback)
+  NS_INTERFACE_MAP_ENTRY(nsIProgressEventSink)
+  NS_INTERFACE_MAP_ENTRY(nsIInterfaceRequestor)
+  NS_INTERFACE_MAP_ENTRY(nsITimerCallback)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIStreamListener)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsXMLHttpRequestXPCOMifier)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(nsXMLHttpRequestXPCOMifier)
+
+// Can't NS_IMPL_CYCLE_COLLECTION( because mXHR has ambiguous
+// inheritance from nsISupports.
+NS_IMPL_CYCLE_COLLECTION_CLASS(nsXMLHttpRequestXPCOMifier)
+
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsXMLHttpRequestXPCOMifier)
+if (tmp->mXHR) {
+  tmp->mXHR->mXPCOMifier = nullptr;
+}
+NS_IMPL_CYCLE_COLLECTION_UNLINK(mXHR)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsXMLHttpRequestXPCOMifier)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mXHR)
+NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
+
+NS_IMETHODIMP
+nsXMLHttpRequestXPCOMifier::GetInterface(const nsIID & aIID, void **aResult)
+{
+  // Return ourselves for the things we implement (except
+  // nsIInterfaceRequestor) and the XHR for the rest.
+  if (!aIID.Equals(NS_GET_IID(nsIInterfaceRequestor))) {
+    nsresult rv = QueryInterface(aIID, aResult);
+    if (NS_SUCCEEDED(rv)) {
+      return rv;
+    }
+  }
+
+  return mXHR->GetInterface(aIID, aResult);
+}
+
+ArrayBufferBuilder::ArrayBufferBuilder()
+  : mDataPtr(nullptr),
+    mCapacity(0),
+    mLength(0),
+    mMapPtr(nullptr)
+{
+}
+
+ArrayBufferBuilder::~ArrayBufferBuilder()
+{
+  reset();
+}
+
+void
+ArrayBufferBuilder::reset()
+{
+  if (mDataPtr) {
+    JS_free(nullptr, mDataPtr);
+  }
+
+  if (mMapPtr) {
+    JS_ReleaseMappedArrayBufferContents(mMapPtr, mLength);
+    mMapPtr = nullptr;
+  }
+
+  mDataPtr = nullptr;
+  mCapacity = mLength = 0;
+}
+
+bool
+ArrayBufferBuilder::setCapacity(uint32_t aNewCap)
+{
+  MOZ_ASSERT(!mMapPtr);
+
+  // To ensure that realloc won't free mDataPtr, use a size of 1
+  // instead of 0.
+  uint8_t* newdata = (uint8_t *) js_realloc(mDataPtr, aNewCap ? aNewCap : 1);
+
+  if (!newdata) {
+    return false;
+  }
+
+  if (aNewCap > mCapacity) {
+    memset(newdata + mCapacity, 0, aNewCap - mCapacity);
+  }
+
+  mDataPtr = newdata;
+  mCapacity = aNewCap;
+  if (mLength > aNewCap) {
+    mLength = aNewCap;
+  }
+
+  return true;
+}
+
+bool
+ArrayBufferBuilder::append(const uint8_t *aNewData, uint32_t aDataLen,
+                           uint32_t aMaxGrowth)
+{
+  MOZ_ASSERT(!mMapPtr);
+
+  CheckedUint32 neededCapacity = mLength;
+  neededCapacity += aDataLen;
+  if (!neededCapacity.isValid()) {
+    return false;
+  }
+  if (mLength + aDataLen > mCapacity) {
+    CheckedUint32 newcap = mCapacity;
+    // Double while under aMaxGrowth or if not specified.
+    if (!aMaxGrowth || mCapacity < aMaxGrowth) {
+      newcap *= 2;
+    } else {
+      newcap += aMaxGrowth;
+    }
+
+    if (!newcap.isValid()) {
+      return false;
+    }
+
+    // But make sure there's always enough to satisfy our request.
+    if (newcap.value() < neededCapacity.value()) {
+      newcap = neededCapacity;
+    }
+
+    if (!setCapacity(newcap.value())) {
+      return false;
+    }
+  }
+
+  // Assert that the region isn't overlapping so we can memcpy.
+  MOZ_ASSERT(!areOverlappingRegions(aNewData, aDataLen, mDataPtr + mLength,
+                                    aDataLen));
+
+  memcpy(mDataPtr + mLength, aNewData, aDataLen);
+  mLength += aDataLen;
+
+  return true;
+}
+
+JSObject*
+ArrayBufferBuilder::getArrayBuffer(JSContext* aCx)
+{
+  if (mMapPtr) {
+    JSObject* obj = JS_NewMappedArrayBufferWithContents(aCx, mLength, mMapPtr);
+    if (!obj) {
+      JS_ReleaseMappedArrayBufferContents(mMapPtr, mLength);
+    }
+    mMapPtr = nullptr;
+
+    // The memory-mapped contents will be released when the ArrayBuffer becomes
+    // detached or is GC'd.
+    return obj;
+  }
+
+  // we need to check for mLength == 0, because nothing may have been
+  // added
+  if (mCapacity > mLength || mLength == 0) {
+    if (!setCapacity(mLength)) {
+      return nullptr;
+    }
+  }
+
+  JSObject* obj = JS_NewArrayBufferWithContents(aCx, mLength, mDataPtr);
+  mLength = mCapacity = 0;
+  if (!obj) {
+    js_free(mDataPtr);
+  }
+  mDataPtr = nullptr;
+  return obj;
+}
+
+nsresult
+ArrayBufferBuilder::mapToFileInPackage(const nsCString& aFile,
+                                       nsIFile* aJarFile)
+{
+  nsresult rv;
+
+  // Open Jar file to get related attributes of target file.
+  RefPtr<nsZipArchive> zip = new nsZipArchive();
+  rv = zip->OpenArchive(aJarFile);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  nsZipItem* zipItem = zip->GetItem(aFile.get());
+  if (!zipItem) {
+    return NS_ERROR_FILE_TARGET_DOES_NOT_EXIST;
+  }
+
+  // If file was added to the package as stored(uncompressed), map to the
+  // offset of file in zip package.
+  if (!zipItem->Compression()) {
+    uint32_t offset = zip->GetDataOffset(zipItem);
+    uint32_t size = zipItem->RealSize();
+    mozilla::AutoFDClose pr_fd;
+    rv = aJarFile->OpenNSPRFileDesc(PR_RDONLY, 0, &pr_fd.rwget());
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+    mMapPtr = JS_CreateMappedArrayBufferContents(PR_FileDesc2NativeHandle(pr_fd),
+                                                 offset, size);
+    if (mMapPtr) {
+      mLength = size;
+      return NS_OK;
+    }
+  }
+  return NS_ERROR_FAILURE;
+}
+
+/* static */ bool
+ArrayBufferBuilder::areOverlappingRegions(const uint8_t* aStart1,
+                                          uint32_t aLength1,
+                                          const uint8_t* aStart2,
+                                          uint32_t aLength2)
+{
+  const uint8_t* end1 = aStart1 + aLength1;
+  const uint8_t* end2 = aStart2 + aLength2;
+
+  const uint8_t* max_start = aStart1 > aStart2 ? aStart1 : aStart2;
+  const uint8_t* min_end   = end1 < end2 ? end1 : end2;
+
+  return max_start < min_end;
+}
+
+RequestHeaders::RequestHeader*
+RequestHeaders::Find(const nsACString& aName)
+{
+  const nsCaseInsensitiveCStringComparator ignoreCase;
+  for (RequestHeaders::RequestHeader& header : mHeaders) {
+    if (header.mName.Equals(aName, ignoreCase)) {
+      return &header;
+    }
+  }
+  return nullptr;
+}
+
+bool
+RequestHeaders::Has(const char* aName)
+{
+  return Has(nsDependentCString(aName));
+}
+
+bool
+RequestHeaders::Has(const nsACString& aName)
+{
+  return !!Find(aName);
+}
+
+void
+RequestHeaders::Get(const char* aName, nsACString& aValue)
+{
+  Get(nsDependentCString(aName), aValue);
+}
+
+void
+RequestHeaders::Get(const nsACString& aName, nsACString& aValue)
+{
+  RequestHeader* header = Find(aName);
+  if (header) {
+    aValue = header->mValue;
+  } else {
+    aValue.SetIsVoid(true);
+  }
+}
+
+void
+RequestHeaders::Set(const char* aName, const nsACString& aValue)
+{
+  Set(nsDependentCString(aName), aValue);
+}
+
+void
+RequestHeaders::Set(const nsACString& aName, const nsACString& aValue)
+{
+  RequestHeader* header = Find(aName);
+  if (header) {
+    header->mValue.Assign(aValue);
+  } else {
+    RequestHeader newHeader = {
+      nsCString(aName), nsCString(aValue)
+    };
+    mHeaders.AppendElement(newHeader);
+  }
+}
+
+void
+RequestHeaders::MergeOrSet(const char* aName, const nsACString& aValue)
+{
+  MergeOrSet(nsDependentCString(aName), aValue);
+}
+
+void
+RequestHeaders::MergeOrSet(const nsACString& aName, const nsACString& aValue)
+{
+  RequestHeader* header = Find(aName);
+  if (header) {
+    header->mValue.AppendLiteral(", ");
+    header->mValue.Append(aValue);
+  } else {
+    RequestHeader newHeader = {
+      nsCString(aName), nsCString(aValue)
+    };
+    mHeaders.AppendElement(newHeader);
+  }
+}
+
+void
+RequestHeaders::Clear()
+{
+  mHeaders.Clear();
+}
+
+void
+RequestHeaders::ApplyToChannel(nsIHttpChannel* aHttpChannel) const
+{
+  for (const RequestHeader& header : mHeaders) {
+    if (header.mValue.IsEmpty()) {
+      aHttpChannel->SetEmptyRequestHeader(header.mName);
+    } else {
+      aHttpChannel->SetRequestHeader(header.mName, header.mValue, false);
+    }
+  }
+}
+
+void
+RequestHeaders::GetCORSUnsafeHeaders(nsTArray<nsCString>& aArray) const
+{
+  static const char *kCrossOriginSafeHeaders[] = {
+    "accept", "accept-language", "content-language", "content-type",
+    "last-event-id"
+  };
+  const uint32_t kCrossOriginSafeHeadersLength =
+    ArrayLength(kCrossOriginSafeHeaders);
+  for (const RequestHeader& header : mHeaders) {
+    bool safe = false;
+    for (uint32_t i = 0; i < kCrossOriginSafeHeadersLength; ++i) {
+      if (header.mName.LowerCaseEqualsASCII(kCrossOriginSafeHeaders[i])) {
+        safe = true;
+        break;
+      }
+    }
+    if (!safe) {
+      aArray.AppendElement(header.mName);
+    }
+  }
+}
+
+RequestHeaders::CharsetIterator::CharsetIterator(nsACString& aSource) :
+  mValid(false),
+  mCurPos(-1),
+  mCurLen(-1),
+  mCutoff(aSource.Length()),
+  mSource(aSource)
+{
+}
+
+bool
+RequestHeaders::CharsetIterator::Equals(const nsACString& aOther,
+                                        const nsCStringComparator& aCmp) const
+{
+  if (mValid) {
+    return Substring(mSource, mCurPos, mCurLen).Equals(aOther, aCmp);
+  } else {
+    return false;
+  }
+}
+
+void
+RequestHeaders::CharsetIterator::Replace(const nsACString& aReplacement)
+{
+  if (mValid) {
+    mSource.Replace(mCurPos, mCurLen, aReplacement);
+    mCurLen = aReplacement.Length();
+  }
+}
+
+bool
+RequestHeaders::CharsetIterator::Next()
+{
+  int32_t start, end;
+  nsAutoCString charset;
+
+  // Look for another charset declaration in the string, limiting the
+  // search to only the characters before the parts we've already searched
+  // (before mCutoff), so that we don't find the same charset twice.
+  NS_ExtractCharsetFromContentType(Substring(mSource, 0, mCutoff),
+                                   charset, &mValid, &start, &end);
+
+  if (!mValid) {
+    return false;
+  }
+
+  // Everything after the = sign is the part of the charset we want.
+  mCurPos = mSource.FindChar('=', start) + 1;
+  mCurLen = end - mCurPos;
+
+  // Special case: the extracted charset is quoted with single quotes.
+  // For the purpose of preserving what was set we want to handle them
+  // as delimiters (although they aren't really).
+  if (charset.Length() >= 2 &&
+      charset.First() == '\'' &&
+      charset.Last() == '\'') {
+    ++mCurPos;
+    mCurLen -= 2;
+  }
+
+  mCutoff = start;
+
+  return true;
+}
+
+} // dom namespace
+} // mozilla namespace