Add m-esr52 at 52.6.0

1 files changed, 3441 insertions, 0 deletions

diff --git a/dom/bindings/BindingUtils.h b/dom/bindings/BindingUtils.h
new file mode 100644
index 000000000..3e58390c9
--- /dev/null
+++ b/dom/bindings/BindingUtils.h
@@ -0,0 +1,3441 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_BindingUtils_h__
+#define mozilla_dom_BindingUtils_h__
+
+#include "jsfriendapi.h"
+#include "jswrapper.h"
+#include "js/Conversions.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/Alignment.h"
+#include "mozilla/Array.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/CycleCollectedJSContext.h"
+#include "mozilla/DeferredFinalize.h"
+#include "mozilla/dom/BindingDeclarations.h"
+#include "mozilla/dom/CallbackObject.h"
+#include "mozilla/dom/DOMJSClass.h"
+#include "mozilla/dom/DOMJSProxyHandler.h"
+#include "mozilla/dom/Exceptions.h"
+#include "mozilla/dom/NonRefcountedDOMObject.h"
+#include "mozilla/dom/Nullable.h"
+#include "mozilla/dom/RootedDictionary.h"
+#include "mozilla/SegmentedVector.h"
+#include "mozilla/dom/workers/Workers.h"
+#include "mozilla/ErrorResult.h"
+#include "mozilla/Likely.h"
+#include "mozilla/MemoryReporting.h"
+#include "nsAutoPtr.h"
+#include "nsIDocument.h"
+#include "nsIGlobalObject.h"
+#include "nsIXPConnect.h"
+#include "nsJSUtils.h"
+#include "nsISupportsImpl.h"
+#include "qsObjectHelper.h"
+#include "xpcpublic.h"
+#include "nsIVariant.h"
+#include "mozilla/dom/FakeString.h"
+
+#include "nsWrapperCacheInlines.h"
+
+class nsIJSID;
+
+namespace mozilla {
+
+enum UseCounter : int16_t;
+
+namespace dom {
+template<typename DataType> class MozMap;
+
+nsresult
+UnwrapArgImpl(JS::Handle<JSObject*> src, const nsIID& iid, void** ppArg);
+
+nsresult
+UnwrapWindowProxyImpl(JS::Handle<JSObject*> src, nsPIDOMWindowOuter** ppArg);
+
+/** Convert a jsval to an XPCOM pointer. Caller must not assume that src will
+    keep the XPCOM pointer rooted. */
+template <class Interface>
+inline nsresult
+UnwrapArg(JS::Handle<JSObject*> src, Interface** ppArg)
+{
+  return UnwrapArgImpl(src, NS_GET_TEMPLATE_IID(Interface),
+                       reinterpret_cast<void**>(ppArg));
+}
+
+template <>
+inline nsresult
+UnwrapArg<nsPIDOMWindowOuter>(JS::Handle<JSObject*> src, nsPIDOMWindowOuter** ppArg)
+{
+  return UnwrapWindowProxyImpl(src, ppArg);
+}
+
+nsresult
+UnwrapXPConnectImpl(JSContext* cx, JS::MutableHandle<JS::Value> src,
+                    const nsIID& iid, void** ppArg);
+
+/*
+ * Convert a jsval being used as a Web IDL interface implementation to an XPCOM
+ * pointer; this is only used for Web IDL interfaces that specify
+ * hasXPConnectImpls.  This is not the same as UnwrapArg because caller _can_
+ * assume that if unwrapping succeeds "val" will be updated so it's rooting the
+ * XPCOM pointer.  Also, UnwrapXPConnect doesn't need to worry about doing
+ * XPCWrappedJS things.
+ *
+ * val must be an ObjectValue.
+ */
+template<class Interface>
+inline nsresult
+UnwrapXPConnect(JSContext* cx, JS::MutableHandle<JS::Value> val,
+                Interface** ppThis)
+{
+  return UnwrapXPConnectImpl(cx, val, NS_GET_TEMPLATE_IID(Interface),
+                             reinterpret_cast<void**>(ppThis));
+}
+
+bool
+ThrowInvalidThis(JSContext* aCx, const JS::CallArgs& aArgs,
+                 bool aSecurityError, const char* aInterfaceName);
+
+bool
+ThrowInvalidThis(JSContext* aCx, const JS::CallArgs& aArgs,
+                 bool aSecurityError, prototypes::ID aProtoId);
+
+// Returns true if the JSClass is used for DOM objects.
+inline bool
+IsDOMClass(const JSClass* clasp)
+{
+  return clasp->flags & JSCLASS_IS_DOMJSCLASS;
+}
+
+inline bool
+IsDOMClass(const js::Class* clasp)
+{
+  return IsDOMClass(Jsvalify(clasp));
+}
+
+// Return true if the JSClass is used for non-proxy DOM objects.
+inline bool
+IsNonProxyDOMClass(const js::Class* clasp)
+{
+  return IsDOMClass(clasp) && !clasp->isProxy();
+}
+
+inline bool
+IsNonProxyDOMClass(const JSClass* clasp)
+{
+  return IsNonProxyDOMClass(js::Valueify(clasp));
+}
+
+// Returns true if the JSClass is used for DOM interface and interface
+// prototype objects.
+inline bool
+IsDOMIfaceAndProtoClass(const JSClass* clasp)
+{
+  return clasp->flags & JSCLASS_IS_DOMIFACEANDPROTOJSCLASS;
+}
+
+inline bool
+IsDOMIfaceAndProtoClass(const js::Class* clasp)
+{
+  return IsDOMIfaceAndProtoClass(Jsvalify(clasp));
+}
+
+static_assert(DOM_OBJECT_SLOT == 0,
+              "DOM_OBJECT_SLOT doesn't match the proxy private slot.  "
+              "Expect bad things");
+template <class T>
+inline T*
+UnwrapDOMObject(JSObject* obj)
+{
+  MOZ_ASSERT(IsDOMClass(js::GetObjectClass(obj)),
+             "Don't pass non-DOM objects to this function");
+
+  JS::Value val = js::GetReservedOrProxyPrivateSlot(obj, DOM_OBJECT_SLOT);
+  return static_cast<T*>(val.toPrivate());
+}
+
+template <class T>
+inline T*
+UnwrapPossiblyNotInitializedDOMObject(JSObject* obj)
+{
+  // This is used by the OjectMoved JSClass hook which can be called before
+  // JS_NewObject has returned and so before we have a chance to set
+  // DOM_OBJECT_SLOT to anything useful.
+
+  MOZ_ASSERT(IsDOMClass(js::GetObjectClass(obj)),
+             "Don't pass non-DOM objects to this function");
+
+  JS::Value val = js::GetReservedOrProxyPrivateSlot(obj, DOM_OBJECT_SLOT);
+  if (val.isUndefined()) {
+    return nullptr;
+  }
+  return static_cast<T*>(val.toPrivate());
+}
+
+inline const DOMJSClass*
+GetDOMClass(const js::Class* clasp)
+{
+  return IsDOMClass(clasp) ? DOMJSClass::FromJSClass(clasp) : nullptr;
+}
+
+inline const DOMJSClass*
+GetDOMClass(JSObject* obj)
+{
+  return GetDOMClass(js::GetObjectClass(obj));
+}
+
+inline nsISupports*
+UnwrapDOMObjectToISupports(JSObject* aObject)
+{
+  const DOMJSClass* clasp = GetDOMClass(aObject);
+  if (!clasp || !clasp->mDOMObjectIsISupports) {
+    return nullptr;
+  }
+
+  return UnwrapPossiblyNotInitializedDOMObject<nsISupports>(aObject);
+}
+
+inline bool
+IsDOMObject(JSObject* obj)
+{
+  return IsDOMClass(js::GetObjectClass(obj));
+}
+
+// There are two valid ways to use UNWRAP_OBJECT: Either obj needs to
+// be a MutableHandle<JSObject*>, or value needs to be a strong-reference
+// smart pointer type (OwningNonNull or RefPtr or nsCOMPtr), in which case obj
+// can be anything that converts to JSObject*.
+#define UNWRAP_OBJECT(Interface, obj, value)                                 \
+  mozilla::dom::UnwrapObject<mozilla::dom::prototypes::id::Interface,        \
+    mozilla::dom::Interface##Binding::NativeType>(obj, value)
+
+// Test whether the given object is an instance of the given interface.
+#define IS_INSTANCE_OF(Interface, obj)                                  \
+  mozilla::dom::IsInstanceOf<mozilla::dom::prototypes::id::Interface,   \
+                             mozilla::dom::Interface##Binding::NativeType>(obj)
+
+// Unwrap the given non-wrapper object.  This can be used with any obj that
+// converts to JSObject*; as long as that JSObject* is live the return value
+// will be valid.
+#define UNWRAP_NON_WRAPPER_OBJECT(Interface, obj, value)                        \
+  mozilla::dom::UnwrapNonWrapperObject<mozilla::dom::prototypes::id::Interface, \
+    mozilla::dom::Interface##Binding::NativeType>(obj, value)
+
+// Some callers don't want to set an exception when unwrapping fails
+// (for example, overload resolution uses unwrapping to tell what sort
+// of thing it's looking at).
+// U must be something that a T* can be assigned to (e.g. T* or an RefPtr<T>).
+//
+// The obj argument will be mutated to point to CheckedUnwrap of itself if the
+// passed-in value is not a DOM object and CheckedUnwrap succeeds.
+//
+// If mayBeWrapper is true, there are three valid ways to invoke
+// UnwrapObjectInternal: Either obj needs to be a class wrapping a
+// MutableHandle<JSObject*>, with an assignment operator that sets the handle to
+// the given object, or U needs to be a strong-reference smart pointer type
+// (OwningNonNull or RefPtr or nsCOMPtr), or the value being stored in "value"
+// must not escape past being tested for falsiness immediately after the
+// UnwrapObjectInternal call.
+//
+// If mayBeWrapper is false, obj can just be a JSObject*, and U anything that a
+// T* can be assigned to.
+namespace binding_detail {
+template <class T, bool mayBeWrapper, typename U, typename V>
+MOZ_ALWAYS_INLINE nsresult
+UnwrapObjectInternal(V& obj, U& value, prototypes::ID protoID,
+                     uint32_t protoDepth)
+{
+  /* First check to see whether we have a DOM object */
+  const DOMJSClass* domClass = GetDOMClass(obj);
+  if (domClass) {
+    /* This object is a DOM object.  Double-check that it is safely
+       castable to T by checking whether it claims to inherit from the
+       class identified by protoID. */
+    if (domClass->mInterfaceChain[protoDepth] == protoID) {
+      value = UnwrapDOMObject<T>(obj);
+      return NS_OK;
+    }
+  }
+
+  /* Maybe we have a security wrapper or outer window? */
+  if (!mayBeWrapper || !js::IsWrapper(obj)) {
+    /* Not a DOM object, not a wrapper, just bail */
+    return NS_ERROR_XPC_BAD_CONVERT_JS;
+  }
+
+  JSObject* unwrappedObj =
+    js::CheckedUnwrap(obj, /* stopAtWindowProxy = */ false);
+  if (!unwrappedObj) {
+    return NS_ERROR_XPC_SECURITY_MANAGER_VETO;
+  }
+  MOZ_ASSERT(!js::IsWrapper(unwrappedObj));
+  // Recursive call is OK, because now we're using false for mayBeWrapper and
+  // we never reach this code if that boolean is false, so can't keep calling
+  // ourselves.
+  //
+  // Unwrap into a temporary pointer, because in general unwrapping into
+  // something of type U might trigger GC (e.g. release the value currently
+  // stored in there, with arbitrary consequences) and invalidate the
+  // "unwrappedObj" pointer.
+  T* tempValue;
+  nsresult rv = UnwrapObjectInternal<T, false>(unwrappedObj, tempValue,
+                                               protoID, protoDepth);
+  if (NS_SUCCEEDED(rv)) {
+    // It's very important to not update "obj" with the "unwrappedObj" value
+    // until we know the unwrap has succeeded.  Otherwise, in a situation in
+    // which we have an overload of object and primitive we could end up
+    // converting to the primitive from the unwrappedObj, whereas we want to do
+    // it from the original object.
+    obj = unwrappedObj;
+    // And now assign to "value"; at this point we don't care if a GC happens
+    // and invalidates unwrappedObj.
+    value = tempValue;
+    return NS_OK;
+  }
+
+  /* It's the wrong sort of DOM object */
+  return NS_ERROR_XPC_BAD_CONVERT_JS;
+}
+
+struct MutableObjectHandleWrapper {
+  explicit MutableObjectHandleWrapper(JS::MutableHandle<JSObject*> aHandle)
+    : mHandle(aHandle)
+  {
+  }
+
+  void operator=(JSObject* aObject)
+  {
+    MOZ_ASSERT(aObject);
+    mHandle.set(aObject);
+  }
+
+  operator JSObject*() const
+  {
+    return mHandle;
+  }
+
+private:
+  JS::MutableHandle<JSObject*> mHandle;
+};
+
+struct MutableValueHandleWrapper {
+  explicit MutableValueHandleWrapper(JS::MutableHandle<JS::Value> aHandle)
+    : mHandle(aHandle)
+  {
+  }
+
+  void operator=(JSObject* aObject)
+  {
+    MOZ_ASSERT(aObject);
+    mHandle.setObject(*aObject);
+  }
+
+  operator JSObject*() const
+  {
+    return &mHandle.toObject();
+  }
+
+private:
+  JS::MutableHandle<JS::Value> mHandle;
+};
+
+} // namespace binding_detail
+
+// UnwrapObject overloads that ensure we have a MutableHandle to keep it alive.
+template<prototypes::ID PrototypeID, class T, typename U>
+MOZ_ALWAYS_INLINE nsresult
+UnwrapObject(JS::MutableHandle<JSObject*> obj, U& value)
+{
+  binding_detail::MutableObjectHandleWrapper wrapper(obj);
+  return binding_detail::UnwrapObjectInternal<T, true>(
+    wrapper, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth);
+}
+
+template<prototypes::ID PrototypeID, class T, typename U>
+MOZ_ALWAYS_INLINE nsresult
+UnwrapObject(JS::MutableHandle<JS::Value> obj, U& value)
+{
+  MOZ_ASSERT(obj.isObject());
+  binding_detail::MutableValueHandleWrapper wrapper(obj);
+  return binding_detail::UnwrapObjectInternal<T, true>(
+    wrapper, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth);
+}
+
+// UnwrapObject overloads that ensure we have a strong ref to keep it alive.
+template<prototypes::ID PrototypeID, class T, typename U>
+MOZ_ALWAYS_INLINE nsresult
+UnwrapObject(JSObject* obj, RefPtr<U>& value)
+{
+  return binding_detail::UnwrapObjectInternal<T, true>(
+    obj, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth);
+}
+
+template<prototypes::ID PrototypeID, class T, typename U>
+MOZ_ALWAYS_INLINE nsresult
+UnwrapObject(JSObject* obj, nsCOMPtr<U>& value)
+{
+  return binding_detail::UnwrapObjectInternal<T, true>(
+    obj, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth);
+}
+
+template<prototypes::ID PrototypeID, class T, typename U>
+MOZ_ALWAYS_INLINE nsresult
+UnwrapObject(JSObject* obj, OwningNonNull<U>& value)
+{
+  return binding_detail::UnwrapObjectInternal<T, true>(
+    obj, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth);
+}
+
+// An UnwrapObject overload that just calls one of the JSObject* ones.
+template<prototypes::ID PrototypeID, class T, typename U>
+MOZ_ALWAYS_INLINE nsresult
+UnwrapObject(JS::Handle<JS::Value> obj, U& value)
+{
+  MOZ_ASSERT(obj.isObject());
+  return UnwrapObject<PrototypeID, T>(&obj.toObject(), value);
+}
+
+template<prototypes::ID PrototypeID, class T>
+MOZ_ALWAYS_INLINE bool
+IsInstanceOf(JSObject* obj)
+{
+  void* ignored;
+  nsresult unwrapped = binding_detail::UnwrapObjectInternal<T, true>(
+    obj, ignored, PrototypeID, PrototypeTraits<PrototypeID>::Depth);
+  return NS_SUCCEEDED(unwrapped);
+}
+
+template<prototypes::ID PrototypeID, class T, typename U>
+MOZ_ALWAYS_INLINE nsresult
+UnwrapNonWrapperObject(JSObject* obj, U& value)
+{
+  MOZ_ASSERT(!js::IsWrapper(obj));
+  return binding_detail::UnwrapObjectInternal<T, false>(
+    obj, value, PrototypeID, PrototypeTraits<PrototypeID>::Depth);
+}
+
+inline bool
+IsNotDateOrRegExp(JSContext* cx, JS::Handle<JSObject*> obj,
+                  bool* notDateOrRegExp)
+{
+  MOZ_ASSERT(obj);
+
+  js::ESClass cls;
+  if (!js::GetBuiltinClass(cx, obj, &cls)) {
+    return false;
+  }
+
+  *notDateOrRegExp = cls != js::ESClass::Date && cls != js::ESClass::RegExp;
+  return true;
+}
+
+MOZ_ALWAYS_INLINE bool
+IsObjectValueConvertibleToDictionary(JSContext* cx,
+                                     JS::Handle<JS::Value> objVal,
+                                     bool* convertible)
+{
+  JS::Rooted<JSObject*> obj(cx, &objVal.toObject());
+  return IsNotDateOrRegExp(cx, obj, convertible);
+}
+
+MOZ_ALWAYS_INLINE bool
+IsConvertibleToDictionary(JSContext* cx, JS::Handle<JS::Value> val,
+                          bool* convertible)
+{
+  if (val.isNullOrUndefined()) {
+    *convertible = true;
+    return true;
+  }
+  if (!val.isObject()) {
+    *convertible = false;
+    return true;
+  }
+  return IsObjectValueConvertibleToDictionary(cx, val, convertible);
+}
+
+MOZ_ALWAYS_INLINE bool
+IsConvertibleToCallbackInterface(JSContext* cx, JS::Handle<JSObject*> obj,
+                                 bool* convertible)
+{
+  return IsNotDateOrRegExp(cx, obj, convertible);
+}
+
+// The items in the protoAndIfaceCache are indexed by the prototypes::id::ID,
+// constructors::id::ID and namedpropertiesobjects::id::ID enums, in that order.
+// The end of the prototype objects should be the start of the interface
+// objects, and the end of the interface objects should be the start of the
+// named properties objects.
+static_assert((size_t)constructors::id::_ID_Start ==
+              (size_t)prototypes::id::_ID_Count &&
+              (size_t)namedpropertiesobjects::id::_ID_Start ==
+              (size_t)constructors::id::_ID_Count,
+              "Overlapping or discontiguous indexes.");
+const size_t kProtoAndIfaceCacheCount = namedpropertiesobjects::id::_ID_Count;
+
+class ProtoAndIfaceCache
+{
+  // The caching strategy we use depends on what sort of global we're dealing
+  // with.  For a window-like global, we want everything to be as fast as
+  // possible, so we use a flat array, indexed by prototype/constructor ID.
+  // For everything else (e.g. globals for JSMs), space is more important than
+  // speed, so we use a two-level lookup table.
+
+  class ArrayCache : public Array<JS::Heap<JSObject*>, kProtoAndIfaceCacheCount>
+  {
+  public:
+    JSObject* EntrySlotIfExists(size_t i) {
+      return (*this)[i];
+    }
+
+    JS::Heap<JSObject*>& EntrySlotOrCreate(size_t i) {
+      return (*this)[i];
+    }
+
+    JS::Heap<JSObject*>& EntrySlotMustExist(size_t i) {
+      return (*this)[i];
+    }
+
+    void Trace(JSTracer* aTracer) {
+      for (size_t i = 0; i < ArrayLength(*this); ++i) {
+        JS::TraceEdge(aTracer, &(*this)[i], "protoAndIfaceCache[i]");
+      }
+    }
+
+    size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) {
+      return aMallocSizeOf(this);
+    }
+  };
+
+  class PageTableCache
+  {
+  public:
+    PageTableCache() {
+      memset(&mPages, 0, sizeof(mPages));
+    }
+
+    ~PageTableCache() {
+      for (size_t i = 0; i < ArrayLength(mPages); ++i) {
+        delete mPages[i];
+      }
+    }
+
+    JSObject* EntrySlotIfExists(size_t i) {
+      MOZ_ASSERT(i < kProtoAndIfaceCacheCount);
+      size_t pageIndex = i / kPageSize;
+      size_t leafIndex = i % kPageSize;
+      Page* p = mPages[pageIndex];
+      if (!p) {
+        return nullptr;
+      }
+      return (*p)[leafIndex];
+    }
+
+    JS::Heap<JSObject*>& EntrySlotOrCreate(size_t i) {
+      MOZ_ASSERT(i < kProtoAndIfaceCacheCount);
+      size_t pageIndex = i / kPageSize;
+      size_t leafIndex = i % kPageSize;
+      Page* p = mPages[pageIndex];
+      if (!p) {
+        p = new Page;
+        mPages[pageIndex] = p;
+      }
+      return (*p)[leafIndex];
+    }
+
+    JS::Heap<JSObject*>& EntrySlotMustExist(size_t i) {
+      MOZ_ASSERT(i < kProtoAndIfaceCacheCount);
+      size_t pageIndex = i / kPageSize;
+      size_t leafIndex = i % kPageSize;
+      Page* p = mPages[pageIndex];
+      MOZ_ASSERT(p);
+      return (*p)[leafIndex];
+    }
+
+    void Trace(JSTracer* trc) {
+      for (size_t i = 0; i < ArrayLength(mPages); ++i) {
+        Page* p = mPages[i];
+        if (p) {
+          for (size_t j = 0; j < ArrayLength(*p); ++j) {
+            JS::TraceEdge(trc, &(*p)[j], "protoAndIfaceCache[i]");
+          }
+        }
+      }
+    }
+
+    size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) {
+      size_t n = aMallocSizeOf(this);
+      for (size_t i = 0; i < ArrayLength(mPages); ++i) {
+        n += aMallocSizeOf(mPages[i]);
+      }
+      return n;
+    }
+
+  private:
+    static const size_t kPageSize = 16;
+    typedef Array<JS::Heap<JSObject*>, kPageSize> Page;
+    static const size_t kNPages = kProtoAndIfaceCacheCount / kPageSize +
+      size_t(bool(kProtoAndIfaceCacheCount % kPageSize));
+    Array<Page*, kNPages> mPages;
+  };
+
+public:
+  enum Kind {
+    WindowLike,
+    NonWindowLike
+  };
+
+  explicit ProtoAndIfaceCache(Kind aKind) : mKind(aKind) {
+    MOZ_COUNT_CTOR(ProtoAndIfaceCache);
+    if (aKind == WindowLike) {
+      mArrayCache = new ArrayCache();
+    } else {
+      mPageTableCache = new PageTableCache();
+    }
+  }
+
+  ~ProtoAndIfaceCache() {
+    if (mKind == WindowLike) {
+      delete mArrayCache;
+    } else {
+      delete mPageTableCache;
+    }
+    MOZ_COUNT_DTOR(ProtoAndIfaceCache);
+  }
+
+#define FORWARD_OPERATION(opName, args)              \
+  do {                                               \
+    if (mKind == WindowLike) {                       \
+      return mArrayCache->opName args;               \
+    } else {                                         \
+      return mPageTableCache->opName args;           \
+    }                                                \
+  } while(0)
+
+  // Return the JSObject stored in slot i, if that slot exists.  If
+  // the slot does not exist, return null.
+  JSObject* EntrySlotIfExists(size_t i) {
+    FORWARD_OPERATION(EntrySlotIfExists, (i));
+  }
+
+  // Return a reference to slot i, creating it if necessary.  There
+  // may not be an object in the returned slot.
+  JS::Heap<JSObject*>& EntrySlotOrCreate(size_t i) {
+    FORWARD_OPERATION(EntrySlotOrCreate, (i));
+  }
+
+  // Return a reference to slot i, which is guaranteed to already
+  // exist.  There may not be an object in the slot, if prototype and
+  // constructor initialization for one of our bindings failed.
+  JS::Heap<JSObject*>& EntrySlotMustExist(size_t i) {
+    FORWARD_OPERATION(EntrySlotMustExist, (i));
+  }
+
+  void Trace(JSTracer *aTracer) {
+    FORWARD_OPERATION(Trace, (aTracer));
+  }
+
+  size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) {
+    size_t n = aMallocSizeOf(this);
+    n += (mKind == WindowLike
+          ? mArrayCache->SizeOfIncludingThis(aMallocSizeOf)
+          : mPageTableCache->SizeOfIncludingThis(aMallocSizeOf));
+    return n;
+  }
+#undef FORWARD_OPERATION
+
+private:
+  union {
+    ArrayCache *mArrayCache;
+    PageTableCache *mPageTableCache;
+  };
+  Kind mKind;
+};
+
+inline void
+AllocateProtoAndIfaceCache(JSObject* obj, ProtoAndIfaceCache::Kind aKind)
+{
+  MOZ_ASSERT(js::GetObjectClass(obj)->flags & JSCLASS_DOM_GLOBAL);
+  MOZ_ASSERT(js::GetReservedSlot(obj, DOM_PROTOTYPE_SLOT).isUndefined());
+
+  ProtoAndIfaceCache* protoAndIfaceCache = new ProtoAndIfaceCache(aKind);
+
+  js::SetReservedSlot(obj, DOM_PROTOTYPE_SLOT,
+                      JS::PrivateValue(protoAndIfaceCache));
+}
+
+#ifdef DEBUG
+struct VerifyTraceProtoAndIfaceCacheCalledTracer : public JS::CallbackTracer
+{
+  bool ok;
+
+  explicit VerifyTraceProtoAndIfaceCacheCalledTracer(JSContext* cx)
+    : JS::CallbackTracer(cx), ok(false)
+  {}
+
+  void onChild(const JS::GCCellPtr&) override {
+    // We don't do anything here, we only want to verify that
+    // TraceProtoAndIfaceCache was called.
+  }
+
+  TracerKind getTracerKind() const override { return TracerKind::VerifyTraceProtoAndIface; }
+};
+#endif
+
+inline void
+TraceProtoAndIfaceCache(JSTracer* trc, JSObject* obj)
+{
+  MOZ_ASSERT(js::GetObjectClass(obj)->flags & JSCLASS_DOM_GLOBAL);
+
+#ifdef DEBUG
+  if (trc->isCallbackTracer() &&
+      (trc->asCallbackTracer()->getTracerKind() ==
+       JS::CallbackTracer::TracerKind::VerifyTraceProtoAndIface)) {
+    // We don't do anything here, we only want to verify that
+    // TraceProtoAndIfaceCache was called.
+    static_cast<VerifyTraceProtoAndIfaceCacheCalledTracer*>(trc)->ok = true;
+    return;
+  }
+#endif
+
+  if (!DOMGlobalHasProtoAndIFaceCache(obj))
+    return;
+  ProtoAndIfaceCache* protoAndIfaceCache = GetProtoAndIfaceCache(obj);
+  protoAndIfaceCache->Trace(trc);
+}
+
+inline void
+DestroyProtoAndIfaceCache(JSObject* obj)
+{
+  MOZ_ASSERT(js::GetObjectClass(obj)->flags & JSCLASS_DOM_GLOBAL);
+
+  if (!DOMGlobalHasProtoAndIFaceCache(obj)) {
+    return;
+  }
+
+  ProtoAndIfaceCache* protoAndIfaceCache = GetProtoAndIfaceCache(obj);
+
+  delete protoAndIfaceCache;
+}
+
+/**
+ * Add constants to an object.
+ */
+bool
+DefineConstants(JSContext* cx, JS::Handle<JSObject*> obj,
+                const ConstantSpec* cs);
+
+struct JSNativeHolder
+{
+  JSNative mNative;
+  const NativePropertyHooks* mPropertyHooks;
+};
+
+struct NamedConstructor
+{
+  const char* mName;
+  const JSNativeHolder mHolder;
+  unsigned mNargs;
+};
+
+/*
+ * Create a DOM interface object (if constructorClass is non-null) and/or a
+ * DOM interface prototype object (if protoClass is non-null).
+ *
+ * global is used as the parent of the interface object and the interface
+ *        prototype object
+ * protoProto is the prototype to use for the interface prototype object.
+ * interfaceProto is the prototype to use for the interface object.  This can be
+ *                null if both constructorClass and constructor are null (as in,
+ *                if we're not creating an interface object at all).
+ * protoClass is the JSClass to use for the interface prototype object.
+ *            This is null if we should not create an interface prototype
+ *            object.
+ * protoCache a pointer to a JSObject pointer where we should cache the
+ *            interface prototype object. This must be null if protoClass is and
+ *            vice versa.
+ * constructorClass is the JSClass to use for the interface object.
+ *                  This is null if we should not create an interface object or
+ *                  if it should be a function object.
+ * constructor holds the JSNative to back the interface object which should be a
+ *             Function, unless constructorClass is non-null in which case it is
+ *             ignored. If this is null and constructorClass is also null then
+ *             we should not create an interface object at all.
+ * ctorNargs is the length of the constructor function; 0 if no constructor
+ * constructorCache a pointer to a JSObject pointer where we should cache the
+ *                  interface object. This must be null if both constructorClass
+ *                  and constructor are null, and non-null otherwise.
+ * properties contains the methods, attributes and constants to be defined on
+ *            objects in any compartment.
+ * chromeProperties contains the methods, attributes and constants to be defined
+ *                  on objects in chrome compartments. This must be null if the
+ *                  interface doesn't have any ChromeOnly properties or if the
+ *                  object is being created in non-chrome compartment.
+ * defineOnGlobal controls whether properties should be defined on the given
+ *                global for the interface object (if any) and named
+ *                constructors (if any) for this interface.  This can be
+ *                false in situations where we want the properties to only
+ *                appear on privileged Xrays but not on the unprivileged
+ *                underlying global.
+ * unscopableNames if not null it points to a null-terminated list of const
+ *                 char* names of the unscopable properties for this interface.
+ * isGlobal if true, we're creating interface objects for a [Global] or
+ *        [PrimaryGlobal] interface, and hence shouldn't define properties on
+ *        the prototype object.
+ *
+ * At least one of protoClass, constructorClass or constructor should be
+ * non-null. If constructorClass or constructor are non-null, the resulting
+ * interface object will be defined on the given global with property name
+ * |name|, which must also be non-null.
+ */
+void
+CreateInterfaceObjects(JSContext* cx, JS::Handle<JSObject*> global,
+                       JS::Handle<JSObject*> protoProto,
+                       const js::Class* protoClass, JS::Heap<JSObject*>* protoCache,
+                       JS::Handle<JSObject*> interfaceProto,
+                       const js::Class* constructorClass,
+                       unsigned ctorNargs, const NamedConstructor* namedConstructors,
+                       JS::Heap<JSObject*>* constructorCache,
+                       const NativeProperties* regularProperties,
+                       const NativeProperties* chromeOnlyProperties,
+                       const char* name, bool defineOnGlobal,
+                       const char* const* unscopableNames,
+                       bool isGlobal);
+
+/**
+ * Define the properties (regular and chrome-only) on obj.
+ *
+ * obj the object to instal the properties on. This should be the interface
+ *     prototype object for regular interfaces and the instance object for
+ *     interfaces marked with Global.
+ * properties contains the methods, attributes and constants to be defined on
+ *            objects in any compartment.
+ * chromeProperties contains the methods, attributes and constants to be defined
+ *                  on objects in chrome compartments. This must be null if the
+ *                  interface doesn't have any ChromeOnly properties or if the
+ *                  object is being created in non-chrome compartment.
+ */
+bool
+DefineProperties(JSContext* cx, JS::Handle<JSObject*> obj,
+                 const NativeProperties* properties,
+                 const NativeProperties* chromeOnlyProperties);
+
+/*
+ * Define the unforgeable methods on an object.
+ */
+bool
+DefineUnforgeableMethods(JSContext* cx, JS::Handle<JSObject*> obj,
+                         const Prefable<const JSFunctionSpec>* props);
+
+/*
+ * Define the unforgeable attributes on an object.
+ */
+bool
+DefineUnforgeableAttributes(JSContext* cx, JS::Handle<JSObject*> obj,
+                            const Prefable<const JSPropertySpec>* props);
+
+#define HAS_MEMBER_TYPEDEFS                                               \
+private:                                                                  \
+  typedef char yes[1];                                                    \
+  typedef char no[2]
+
+#ifdef _MSC_VER
+#define HAS_MEMBER_CHECK(_name)                                           \
+  template<typename V> static yes& Check##_name(char (*)[(&V::_name == 0) + 1])
+#else
+#define HAS_MEMBER_CHECK(_name)                                           \
+  template<typename V> static yes& Check##_name(char (*)[sizeof(&V::_name) + 1])
+#endif
+
+#define HAS_MEMBER(_memberName, _valueName)                               \
+private:                                                                  \
+  HAS_MEMBER_CHECK(_memberName);                                          \
+  template<typename V> static no& Check##_memberName(...);                \
+                                                                          \
+public:                                                                   \
+  static bool const _valueName =                                          \
+    sizeof(Check##_memberName<T>(nullptr)) == sizeof(yes)
+
+template<class T>
+struct NativeHasMember
+{
+  HAS_MEMBER_TYPEDEFS;
+
+  HAS_MEMBER(GetParentObject, GetParentObject);
+  HAS_MEMBER(WrapObject, WrapObject);
+};
+
+template<class T>
+struct IsSmartPtr
+{
+  HAS_MEMBER_TYPEDEFS;
+
+  HAS_MEMBER(get, value);
+};
+
+template<class T>
+struct IsRefcounted
+{
+  HAS_MEMBER_TYPEDEFS;
+
+  HAS_MEMBER(AddRef, HasAddref);
+  HAS_MEMBER(Release, HasRelease);
+
+public:
+  static bool const value = HasAddref && HasRelease;
+
+private:
+  // This struct only works if T is fully declared (not just forward declared).
+  // The IsBaseOf check will ensure that, we don't really need it for any other
+  // reason (the static assert will of course always be true).
+  static_assert(!IsBaseOf<nsISupports, T>::value || IsRefcounted::value,
+                "Classes derived from nsISupports are refcounted!");
+
+};
+
+#undef HAS_MEMBER
+#undef HAS_MEMBER_CHECK
+#undef HAS_MEMBER_TYPEDEFS
+
+#ifdef DEBUG
+template <class T, bool isISupports=IsBaseOf<nsISupports, T>::value>
+struct
+CheckWrapperCacheCast
+{
+  static bool Check()
+  {
+    return reinterpret_cast<uintptr_t>(
+      static_cast<nsWrapperCache*>(
+        reinterpret_cast<T*>(1))) == 1;
+  }
+};
+template <class T>
+struct
+CheckWrapperCacheCast<T, true>
+{
+  static bool Check()
+  {
+    return true;
+  }
+};
+#endif
+
+MOZ_ALWAYS_INLINE bool
+CouldBeDOMBinding(void*)
+{
+  return true;
+}
+
+MOZ_ALWAYS_INLINE bool
+CouldBeDOMBinding(nsWrapperCache* aCache)
+{
+  return aCache->IsDOMBinding();
+}
+
+inline bool
+TryToOuterize(JS::MutableHandle<JS::Value> rval)
+{
+  if (js::IsWindow(&rval.toObject())) {
+    JSObject* obj = js::ToWindowProxyIfWindow(&rval.toObject());
+    MOZ_ASSERT(obj);
+    rval.set(JS::ObjectValue(*obj));
+  }
+
+  return true;
+}
+
+// Make sure to wrap the given string value into the right compartment, as
+// needed.
+MOZ_ALWAYS_INLINE
+bool
+MaybeWrapStringValue(JSContext* cx, JS::MutableHandle<JS::Value> rval)
+{
+  MOZ_ASSERT(rval.isString());
+  JSString* str = rval.toString();
+  if (JS::GetStringZone(str) != js::GetContextZone(cx)) {
+    return JS_WrapValue(cx, rval);
+  }
+  return true;
+}
+
+// Make sure to wrap the given object value into the right compartment as
+// needed.  This will work correctly, but possibly slowly, on all objects.
+MOZ_ALWAYS_INLINE
+bool
+MaybeWrapObjectValue(JSContext* cx, JS::MutableHandle<JS::Value> rval)
+{
+  MOZ_ASSERT(rval.isObject());
+
+  // Cross-compartment always requires wrapping.
+  JSObject* obj = &rval.toObject();
+  if (js::GetObjectCompartment(obj) != js::GetContextCompartment(cx)) {
+    return JS_WrapValue(cx, rval);
+  }
+
+  // We're same-compartment, but even then we might need to wrap
+  // objects specially.  Check for that.
+  if (IsDOMObject(obj)) {
+    return TryToOuterize(rval);
+  }
+
+  // It's not a WebIDL object, so it's OK to just leave it as-is: only WebIDL
+  // objects (specifically only windows) require outerization.
+  return true;
+}
+
+// Like MaybeWrapObjectValue, but also allows null
+MOZ_ALWAYS_INLINE
+bool
+MaybeWrapObjectOrNullValue(JSContext* cx, JS::MutableHandle<JS::Value> rval)
+{
+  MOZ_ASSERT(rval.isObjectOrNull());
+  if (rval.isNull()) {
+    return true;
+  }
+  return MaybeWrapObjectValue(cx, rval);
+}
+
+// Wrapping for objects that are known to not be DOM or XPConnect objects
+MOZ_ALWAYS_INLINE
+bool
+MaybeWrapNonDOMObjectValue(JSContext* cx, JS::MutableHandle<JS::Value> rval)
+{
+  MOZ_ASSERT(rval.isObject());
+  MOZ_ASSERT(!GetDOMClass(&rval.toObject()));
+  MOZ_ASSERT(!(js::GetObjectClass(&rval.toObject())->flags &
+               JSCLASS_PRIVATE_IS_NSISUPPORTS));
+
+  JSObject* obj = &rval.toObject();
+  if (js::GetObjectCompartment(obj) == js::GetContextCompartment(cx)) {
+    return true;
+  }
+  return JS_WrapValue(cx, rval);
+}
+
+// Like MaybeWrapNonDOMObjectValue but allows null
+MOZ_ALWAYS_INLINE
+bool
+MaybeWrapNonDOMObjectOrNullValue(JSContext* cx, JS::MutableHandle<JS::Value> rval)
+{
+  MOZ_ASSERT(rval.isObjectOrNull());
+  if (rval.isNull()) {
+    return true;
+  }
+  return MaybeWrapNonDOMObjectValue(cx, rval);
+}
+
+// If rval is a gcthing and is not in the compartment of cx, wrap rval
+// into the compartment of cx (typically by replacing it with an Xray or
+// cross-compartment wrapper around the original object).
+MOZ_ALWAYS_INLINE bool
+MaybeWrapValue(JSContext* cx, JS::MutableHandle<JS::Value> rval)
+{
+  if (rval.isString()) {
+    return MaybeWrapStringValue(cx, rval);
+  }
+
+  if (!rval.isObject()) {
+    return true;
+  }
+
+  return MaybeWrapObjectValue(cx, rval);
+}
+
+namespace binding_detail {
+enum GetOrCreateReflectorWrapBehavior {
+  eWrapIntoContextCompartment,
+  eDontWrapIntoContextCompartment
+};
+
+template <class T>
+struct TypeNeedsOuterization
+{
+  // We only need to outerize Window objects, so anything inheriting from
+  // nsGlobalWindow (which inherits from EventTarget itself).
+  static const bool value =
+    IsBaseOf<nsGlobalWindow, T>::value || IsSame<EventTarget, T>::value;
+};
+
+#ifdef DEBUG
+template<typename T, bool isISupports=IsBaseOf<nsISupports, T>::value>
+struct CheckWrapperCacheTracing
+{
+  static inline void Check(T* aObject)
+  {
+  }
+};
+
+template<typename T>
+struct CheckWrapperCacheTracing<T, true>
+{
+  static void Check(T* aObject)
+  {
+    // Rooting analysis thinks QueryInterface may GC, but we're dealing with
+    // a subset of QueryInterface, C++ only types here.
+    JS::AutoSuppressGCAnalysis nogc;
+
+    nsWrapperCache* wrapperCacheFromQI = nullptr;
+    aObject->QueryInterface(NS_GET_IID(nsWrapperCache),
+                            reinterpret_cast<void**>(&wrapperCacheFromQI));
+
+    MOZ_ASSERT(wrapperCacheFromQI,
+               "Missing nsWrapperCache from QueryInterface implementation?");
+
+    if (!wrapperCacheFromQI->GetWrapperPreserveColor()) {
+      // Can't assert that we trace the wrapper, since we don't have any
+      // wrapper to trace.
+      return;
+    }
+
+    nsISupports* ccISupports = nullptr;
+    aObject->QueryInterface(NS_GET_IID(nsCycleCollectionISupports),
+                            reinterpret_cast<void**>(&ccISupports));
+    MOZ_ASSERT(ccISupports,
+               "nsWrapperCache object which isn't cycle collectable?");
+
+    nsXPCOMCycleCollectionParticipant* participant = nullptr;
+    CallQueryInterface(ccISupports, &participant);
+    MOZ_ASSERT(participant, "Can't QI to CycleCollectionParticipant?");
+
+    bool wasPreservingWrapper = wrapperCacheFromQI->PreservingWrapper();
+    wrapperCacheFromQI->SetPreservingWrapper(true);
+    wrapperCacheFromQI->CheckCCWrapperTraversal(ccISupports, participant);
+    wrapperCacheFromQI->SetPreservingWrapper(wasPreservingWrapper);
+  }
+};
+
+void
+AssertReflectorHasGivenProto(JSContext* aCx, JSObject* aReflector,
+                             JS::Handle<JSObject*> aGivenProto);
+#endif // DEBUG
+
+template <class T, GetOrCreateReflectorWrapBehavior wrapBehavior>
+MOZ_ALWAYS_INLINE bool
+DoGetOrCreateDOMReflector(JSContext* cx, T* value,
+                          JS::Handle<JSObject*> givenProto,
+                          JS::MutableHandle<JS::Value> rval)
+{
+  MOZ_ASSERT(value);
+  // We can get rid of this when we remove support for hasXPConnectImpls.
+  bool couldBeDOMBinding = CouldBeDOMBinding(value);
+  JSObject* obj = value->GetWrapper();
+  if (obj) {
+#ifdef DEBUG
+    AssertReflectorHasGivenProto(cx, obj, givenProto);
+    // Have to reget obj because AssertReflectorHasGivenProto can
+    // trigger gc so the pointer may now be invalid.
+    obj = value->GetWrapper();
+#endif
+  } else {
+    // Inline this here while we have non-dom objects in wrapper caches.
+    if (!couldBeDOMBinding) {
+      return false;
+    }
+
+    obj = value->WrapObject(cx, givenProto);
+    if (!obj) {
+      // At this point, obj is null, so just return false.
+      // Callers seem to be testing JS_IsExceptionPending(cx) to
+      // figure out whether WrapObject() threw.
+      return false;
+    }
+
+#ifdef DEBUG
+    if (IsBaseOf<nsWrapperCache, T>::value) {
+      CheckWrapperCacheTracing<T>::Check(value);
+    }
+#endif
+  }
+
+#ifdef DEBUG
+  const DOMJSClass* clasp = GetDOMClass(obj);
+  // clasp can be null if the cache contained a non-DOM object.
+  if (clasp) {
+    // Some sanity asserts about our object.  Specifically:
+    // 1)  If our class claims we're nsISupports, we better be nsISupports
+    //     XXXbz ideally, we could assert that reinterpret_cast to nsISupports
+    //     does the right thing, but I don't see a way to do it.  :(
+    // 2)  If our class doesn't claim we're nsISupports we better be
+    //     reinterpret_castable to nsWrapperCache.
+    MOZ_ASSERT(clasp, "What happened here?");
+    MOZ_ASSERT_IF(clasp->mDOMObjectIsISupports, (IsBaseOf<nsISupports, T>::value));
+    MOZ_ASSERT(CheckWrapperCacheCast<T>::Check());
+  }
+#endif
+
+  rval.set(JS::ObjectValue(*obj));
+
+  bool sameCompartment =
+    js::GetObjectCompartment(obj) == js::GetContextCompartment(cx);
+  if (sameCompartment && couldBeDOMBinding) {
+    return TypeNeedsOuterization<T>::value ? TryToOuterize(rval) : true;
+  }
+
+  if (wrapBehavior == eDontWrapIntoContextCompartment) {
+    if (TypeNeedsOuterization<T>::value) {
+      JSAutoCompartment ac(cx, obj);
+      return TryToOuterize(rval);
+    }
+
+    return true;
+  }
+
+  return JS_WrapValue(cx, rval);
+}
+
+} // namespace binding_detail
+
+// Create a JSObject wrapping "value", if there isn't one already, and store it
+// in rval.  "value" must be a concrete class that implements a
+// GetWrapperPreserveColor() which can return its existing wrapper, if any, and
+// a WrapObject() which will try to create a wrapper. Typically, this is done by
+// having "value" inherit from nsWrapperCache.
+//
+// The value stored in rval will be ready to be exposed to whatever JS
+// is running on cx right now.  In particular, it will be in the
+// compartment of cx, and outerized as needed.
+template <class T>
+MOZ_ALWAYS_INLINE bool
+GetOrCreateDOMReflector(JSContext* cx, T* value,
+                        JS::MutableHandle<JS::Value> rval,
+                        JS::Handle<JSObject*> givenProto = nullptr)
+{
+  using namespace binding_detail;
+  return DoGetOrCreateDOMReflector<T, eWrapIntoContextCompartment>(cx, value,
+                                                                   givenProto,
+                                                                   rval);
+}
+
+// Like GetOrCreateDOMReflector but doesn't wrap into the context compartment,
+// and hence does not actually require cx to be in a compartment.
+template <class T>
+MOZ_ALWAYS_INLINE bool
+GetOrCreateDOMReflectorNoWrap(JSContext* cx, T* value,
+                              JS::MutableHandle<JS::Value> rval)
+{
+  using namespace binding_detail;
+  return DoGetOrCreateDOMReflector<T, eDontWrapIntoContextCompartment>(cx,
+                                                                       value,
+                                                                       nullptr,
+                                                                       rval);
+}
+
+// Create a JSObject wrapping "value", for cases when "value" is a
+// non-wrapper-cached object using WebIDL bindings.  "value" must implement a
+// WrapObject() method taking a JSContext and a scope.
+template <class T>
+inline bool
+WrapNewBindingNonWrapperCachedObject(JSContext* cx,
+                                     JS::Handle<JSObject*> scopeArg,
+                                     T* value,
+                                     JS::MutableHandle<JS::Value> rval,
+                                     JS::Handle<JSObject*> givenProto = nullptr)
+{
+  static_assert(IsRefcounted<T>::value, "Don't pass owned classes in here.");
+  MOZ_ASSERT(value);
+  // We try to wrap in the compartment of the underlying object of "scope"
+  JS::Rooted<JSObject*> obj(cx);
+  {
+    // scope for the JSAutoCompartment so that we restore the compartment
+    // before we call JS_WrapValue.
+    Maybe<JSAutoCompartment> ac;
+    // Maybe<Handle> doesn't so much work, and in any case, adding
+    // more Maybe (one for a Rooted and one for a Handle) adds more
+    // code (and branches!) than just adding a single rooted.
+    JS::Rooted<JSObject*> scope(cx, scopeArg);
+    JS::Rooted<JSObject*> proto(cx, givenProto);
+    if (js::IsWrapper(scope)) {
+      scope = js::CheckedUnwrap(scope, /* stopAtWindowProxy = */ false);
+      if (!scope)
+        return false;
+      ac.emplace(cx, scope);
+      if (!JS_WrapObject(cx, &proto)) {
+        return false;
+      }
+    }
+
+    MOZ_ASSERT(js::IsObjectInContextCompartment(scope, cx));
+    if (!value->WrapObject(cx, proto, &obj)) {
+      return false;
+    }
+  }
+
+  // We can end up here in all sorts of compartments, per above.  Make
+  // sure to JS_WrapValue!
+  rval.set(JS::ObjectValue(*obj));
+  return MaybeWrapObjectValue(cx, rval);
+}
+
+// Create a JSObject wrapping "value", for cases when "value" is a
+// non-wrapper-cached owned object using WebIDL bindings.  "value" must implement a
+// WrapObject() method taking a JSContext, a scope, and a boolean outparam that
+// is true if the JSObject took ownership
+template <class T>
+inline bool
+WrapNewBindingNonWrapperCachedObject(JSContext* cx,
+                                     JS::Handle<JSObject*> scopeArg,
+                                     nsAutoPtr<T>& value,
+                                     JS::MutableHandle<JS::Value> rval,
+                                     JS::Handle<JSObject*> givenProto = nullptr)
+{
+  static_assert(!IsRefcounted<T>::value, "Only pass owned classes in here.");
+  // We do a runtime check on value, because otherwise we might in
+  // fact end up wrapping a null and invoking methods on it later.
+  if (!value) {
+    NS_RUNTIMEABORT("Don't try to wrap null objects");
+  }
+  // We try to wrap in the compartment of the underlying object of "scope"
+  JS::Rooted<JSObject*> obj(cx);
+  {
+    // scope for the JSAutoCompartment so that we restore the compartment
+    // before we call JS_WrapValue.
+    Maybe<JSAutoCompartment> ac;
+    // Maybe<Handle> doesn't so much work, and in any case, adding
+    // more Maybe (one for a Rooted and one for a Handle) adds more
+    // code (and branches!) than just adding a single rooted.
+    JS::Rooted<JSObject*> scope(cx, scopeArg);
+    JS::Rooted<JSObject*> proto(cx, givenProto);
+    if (js::IsWrapper(scope)) {
+      scope = js::CheckedUnwrap(scope, /* stopAtWindowProxy = */ false);
+      if (!scope)
+        return false;
+      ac.emplace(cx, scope);
+      if (!JS_WrapObject(cx, &proto)) {
+        return false;
+      }
+    }
+
+    MOZ_ASSERT(js::IsObjectInContextCompartment(scope, cx));
+    if (!value->WrapObject(cx, proto, &obj)) {
+      return false;
+    }
+
+    value.forget();
+  }
+
+  // We can end up here in all sorts of compartments, per above.  Make
+  // sure to JS_WrapValue!
+  rval.set(JS::ObjectValue(*obj));
+  return MaybeWrapObjectValue(cx, rval);
+}
+
+// Helper for smart pointers (nsRefPtr/nsCOMPtr).
+template <template <typename> class SmartPtr, typename T,
+          typename U=typename EnableIf<IsRefcounted<T>::value, T>::Type,
+          typename V=typename EnableIf<IsSmartPtr<SmartPtr<T>>::value, T>::Type>
+inline bool
+WrapNewBindingNonWrapperCachedObject(JSContext* cx, JS::Handle<JSObject*> scope,
+                                     const SmartPtr<T>& value,
+                                     JS::MutableHandle<JS::Value> rval,
+                                     JS::Handle<JSObject*> givenProto = nullptr)
+{
+  return WrapNewBindingNonWrapperCachedObject(cx, scope, value.get(), rval,
+                                              givenProto);
+}
+
+// Helper for object references (as opposed to pointers).
+template <typename T,
+          typename U=typename EnableIf<!IsSmartPtr<T>::value, T>::Type>
+inline bool
+WrapNewBindingNonWrapperCachedObject(JSContext* cx, JS::Handle<JSObject*> scope,
+                                     T& value,
+                                     JS::MutableHandle<JS::Value> rval,
+                                     JS::Handle<JSObject*> givenProto = nullptr)
+{
+  return WrapNewBindingNonWrapperCachedObject(cx, scope, &value, rval,
+                                              givenProto);
+}
+
+// Only set allowNativeWrapper to false if you really know you need it, if in
+// doubt use true. Setting it to false disables security wrappers.
+bool
+NativeInterface2JSObjectAndThrowIfFailed(JSContext* aCx,
+                                         JS::Handle<JSObject*> aScope,
+                                         JS::MutableHandle<JS::Value> aRetval,
+                                         xpcObjectHelper& aHelper,
+                                         const nsIID* aIID,
+                                         bool aAllowNativeWrapper);
+
+/**
+ * A method to handle new-binding wrap failure, by possibly falling back to
+ * wrapping as a non-new-binding object.
+ */
+template <class T>
+MOZ_ALWAYS_INLINE bool
+HandleNewBindingWrappingFailure(JSContext* cx, JS::Handle<JSObject*> scope,
+                                T* value, JS::MutableHandle<JS::Value> rval)
+{
+  if (JS_IsExceptionPending(cx)) {
+    return false;
+  }
+
+  qsObjectHelper helper(value, GetWrapperCache(value));
+  return NativeInterface2JSObjectAndThrowIfFailed(cx, scope, rval,
+                                                  helper, nullptr, true);
+}
+
+// Helper for calling HandleNewBindingWrappingFailure with smart pointers
+// (nsAutoPtr/nsRefPtr/nsCOMPtr) or references.
+
+template <class T, bool isSmartPtr=IsSmartPtr<T>::value>
+struct HandleNewBindingWrappingFailureHelper
+{
+  static inline bool Wrap(JSContext* cx, JS::Handle<JSObject*> scope,
+                          const T& value, JS::MutableHandle<JS::Value> rval)
+  {
+    return HandleNewBindingWrappingFailure(cx, scope, value.get(), rval);
+  }
+};
+
+template <class T>
+struct HandleNewBindingWrappingFailureHelper<T, false>
+{
+  static inline bool Wrap(JSContext* cx, JS::Handle<JSObject*> scope, T& value,
+                          JS::MutableHandle<JS::Value> rval)
+  {
+    return HandleNewBindingWrappingFailure(cx, scope, &value, rval);
+  }
+};
+
+template<class T>
+inline bool
+HandleNewBindingWrappingFailure(JSContext* cx, JS::Handle<JSObject*> scope,
+                                T& value, JS::MutableHandle<JS::Value> rval)
+{
+  return HandleNewBindingWrappingFailureHelper<T>::Wrap(cx, scope, value, rval);
+}
+
+template<bool Fatal>
+inline bool
+EnumValueNotFound(JSContext* cx, JS::HandleString str, const char* type,
+                  const char* sourceDescription);
+
+template<>
+inline bool
+EnumValueNotFound<false>(JSContext* cx, JS::HandleString str, const char* type,
+                         const char* sourceDescription)
+{
+  // TODO: Log a warning to the console.
+  return true;
+}
+
+template<>
+inline bool
+EnumValueNotFound<true>(JSContext* cx, JS::HandleString str, const char* type,
+                        const char* sourceDescription)
+{
+  JSAutoByteString deflated;
+  if (!deflated.encodeUtf8(cx, str)) {
+    return false;
+  }
+  return ThrowErrorMessage(cx, MSG_INVALID_ENUM_VALUE, sourceDescription,
+                           deflated.ptr(), type);
+}
+
+template<typename CharT>
+inline int
+FindEnumStringIndexImpl(const CharT* chars, size_t length, const EnumEntry* values)
+{
+  int i = 0;
+  for (const EnumEntry* value = values; value->value; ++value, ++i) {
+    if (length != value->length) {
+      continue;
+    }
+
+    bool equal = true;
+    const char* val = value->value;
+    for (size_t j = 0; j != length; ++j) {
+      if (unsigned(val[j]) != unsigned(chars[j])) {
+        equal = false;
+        break;
+      }
+    }
+
+    if (equal) {
+      return i;
+    }
+  }
+
+  return -1;
+}
+
+template<bool InvalidValueFatal>
+inline bool
+FindEnumStringIndex(JSContext* cx, JS::Handle<JS::Value> v, const EnumEntry* values,
+                    const char* type, const char* sourceDescription, int* index)
+{
+  // JS_StringEqualsAscii is slow as molasses, so don't use it here.
+  JS::RootedString str(cx, JS::ToString(cx, v));
+  if (!str) {
+    return false;
+  }
+
+  {
+    size_t length;
+    JS::AutoCheckCannotGC nogc;
+    if (js::StringHasLatin1Chars(str)) {
+      const JS::Latin1Char* chars = JS_GetLatin1StringCharsAndLength(cx, nogc, str,
+                                                                     &length);
+      if (!chars) {
+        return false;
+      }
+      *index = FindEnumStringIndexImpl(chars, length, values);
+    } else {
+      const char16_t* chars = JS_GetTwoByteStringCharsAndLength(cx, nogc, str,
+                                                                &length);
+      if (!chars) {
+        return false;
+      }
+      *index = FindEnumStringIndexImpl(chars, length, values);
+    }
+    if (*index >= 0) {
+      return true;
+    }
+  }
+
+  return EnumValueNotFound<InvalidValueFatal>(cx, str, type, sourceDescription);
+}
+
+inline nsWrapperCache*
+GetWrapperCache(const ParentObject& aParentObject)
+{
+  return aParentObject.mWrapperCache;
+}
+
+template<class T>
+inline T*
+GetParentPointer(T* aObject)
+{
+  return aObject;
+}
+
+inline nsISupports*
+GetParentPointer(const ParentObject& aObject)
+{
+  return aObject.mObject;
+}
+
+template <typename T>
+inline bool
+GetUseXBLScope(T* aParentObject)
+{
+  return false;
+}
+
+inline bool
+GetUseXBLScope(const ParentObject& aParentObject)
+{
+  return aParentObject.mUseXBLScope;
+}
+
+template<class T>
+inline void
+ClearWrapper(T* p, nsWrapperCache* cache)
+{
+  cache->ClearWrapper();
+}
+
+template<class T>
+inline void
+ClearWrapper(T* p, void*)
+{
+  nsWrapperCache* cache;
+  CallQueryInterface(p, &cache);
+  ClearWrapper(p, cache);
+}
+
+template<class T>
+inline void
+UpdateWrapper(T* p, nsWrapperCache* cache, JSObject* obj, const JSObject* old)
+{
+  JS::AutoAssertGCCallback inCallback(obj);
+  cache->UpdateWrapper(obj, old);
+}
+
+template<class T>
+inline void
+UpdateWrapper(T* p, void*, JSObject* obj, const JSObject* old)
+{
+  JS::AutoAssertGCCallback inCallback(obj);
+  nsWrapperCache* cache;
+  CallQueryInterface(p, &cache);
+  UpdateWrapper(p, cache, obj, old);
+}
+
+// Attempt to preserve the wrapper, if any, for a Paris DOM bindings object.
+// Return true if we successfully preserved the wrapper, or there is no wrapper
+// to preserve. In the latter case we don't need to preserve the wrapper, because
+// the object can only be obtained by JS once, or they cannot be meaningfully
+// owned from the native side.
+//
+// This operation will return false only for non-nsISupports cycle-collected
+// objects, because we cannot determine if they are wrappercached or not.
+bool
+TryPreserveWrapper(JSObject* obj);
+
+// Can only be called with a DOM JSClass.
+bool
+InstanceClassHasProtoAtDepth(const js::Class* clasp,
+                             uint32_t protoID, uint32_t depth);
+
+// Only set allowNativeWrapper to false if you really know you need it, if in
+// doubt use true. Setting it to false disables security wrappers.
+bool
+XPCOMObjectToJsval(JSContext* cx, JS::Handle<JSObject*> scope,
+                   xpcObjectHelper& helper, const nsIID* iid,
+                   bool allowNativeWrapper, JS::MutableHandle<JS::Value> rval);
+
+// Special-cased wrapping for variants
+bool
+VariantToJsval(JSContext* aCx, nsIVariant* aVariant,
+               JS::MutableHandle<JS::Value> aRetval);
+
+// Wrap an object "p" which is not using WebIDL bindings yet.  This _will_
+// actually work on WebIDL binding objects that are wrappercached, but will be
+// much slower than GetOrCreateDOMReflector.  "cache" must either be null or be
+// the nsWrapperCache for "p".
+template<class T>
+inline bool
+WrapObject(JSContext* cx, T* p, nsWrapperCache* cache, const nsIID* iid,
+           JS::MutableHandle<JS::Value> rval)
+{
+  if (xpc_FastGetCachedWrapper(cx, cache, rval))
+    return true;
+  qsObjectHelper helper(p, cache);
+  JS::Rooted<JSObject*> scope(cx, JS::CurrentGlobalOrNull(cx));
+  return XPCOMObjectToJsval(cx, scope, helper, iid, true, rval);
+}
+
+// A specialization of the above for nsIVariant, because that needs to
+// do something different.
+template<>
+inline bool
+WrapObject<nsIVariant>(JSContext* cx, nsIVariant* p,
+                       nsWrapperCache* cache, const nsIID* iid,
+                       JS::MutableHandle<JS::Value> rval)
+{
+  MOZ_ASSERT(iid);
+  MOZ_ASSERT(iid->Equals(NS_GET_IID(nsIVariant)));
+  return VariantToJsval(cx, p, rval);
+}
+
+// Wrap an object "p" which is not using WebIDL bindings yet.  Just like the
+// variant that takes an nsWrapperCache above, but will try to auto-derive the
+// nsWrapperCache* from "p".
+template<class T>
+inline bool
+WrapObject(JSContext* cx, T* p, const nsIID* iid,
+           JS::MutableHandle<JS::Value> rval)
+{
+  return WrapObject(cx, p, GetWrapperCache(p), iid, rval);
+}
+
+// Just like the WrapObject above, but without requiring you to pick which
+// interface you're wrapping as.  This should only be used for objects that have
+// classinfo, for which it doesn't matter what IID is used to wrap.
+template<class T>
+inline bool
+WrapObject(JSContext* cx, T* p, JS::MutableHandle<JS::Value> rval)
+{
+  return WrapObject(cx, p, nullptr, rval);
+}
+
+// Helper to make it possible to wrap directly out of an nsCOMPtr
+template<class T>
+inline bool
+WrapObject(JSContext* cx, const nsCOMPtr<T>& p,
+           const nsIID* iid, JS::MutableHandle<JS::Value> rval)
+{
+  return WrapObject(cx, p.get(), iid, rval);
+}
+
+// Helper to make it possible to wrap directly out of an nsCOMPtr
+template<class T>
+inline bool
+WrapObject(JSContext* cx, const nsCOMPtr<T>& p,
+           JS::MutableHandle<JS::Value> rval)
+{
+  return WrapObject(cx, p, nullptr, rval);
+}
+
+// Helper to make it possible to wrap directly out of an nsRefPtr
+template<class T>
+inline bool
+WrapObject(JSContext* cx, const RefPtr<T>& p,
+           const nsIID* iid, JS::MutableHandle<JS::Value> rval)
+{
+  return WrapObject(cx, p.get(), iid, rval);
+}
+
+// Helper to make it possible to wrap directly out of an nsRefPtr
+template<class T>
+inline bool
+WrapObject(JSContext* cx, const RefPtr<T>& p,
+           JS::MutableHandle<JS::Value> rval)
+{
+  return WrapObject(cx, p, nullptr, rval);
+}
+
+// Specialization to make it easy to use WrapObject in codegen.
+template<>
+inline bool
+WrapObject<JSObject>(JSContext* cx, JSObject* p,
+                     JS::MutableHandle<JS::Value> rval)
+{
+  rval.set(JS::ObjectOrNullValue(p));
+  return true;
+}
+
+inline bool
+WrapObject(JSContext* cx, JSObject& p, JS::MutableHandle<JS::Value> rval)
+{
+  rval.set(JS::ObjectValue(p));
+  return true;
+}
+
+// Given an object "p" that inherits from nsISupports, wrap it and return the
+// result.  Null is returned on wrapping failure.  This is somewhat similar to
+// WrapObject() above, but does NOT allow Xrays around the result, since we
+// don't want those for our parent object.
+template<typename T>
+static inline JSObject*
+WrapNativeISupports(JSContext* cx, T* p, nsWrapperCache* cache)
+{
+  qsObjectHelper helper(ToSupports(p), cache);
+  JS::Rooted<JSObject*> scope(cx, JS::CurrentGlobalOrNull(cx));
+  JS::Rooted<JS::Value> v(cx);
+  return XPCOMObjectToJsval(cx, scope, helper, nullptr, false, &v) ?
+         v.toObjectOrNull() :
+         nullptr;
+}
+
+
+// Fallback for when our parent is not a WebIDL binding object.
+template<typename T, bool isISupports=IsBaseOf<nsISupports, T>::value>
+struct WrapNativeFallback
+{
+  static inline JSObject* Wrap(JSContext* cx, T* parent, nsWrapperCache* cache)
+  {
+    return nullptr;
+  }
+};
+
+// Fallback for when our parent is not a WebIDL binding object but _is_ an
+// nsISupports object.
+template<typename T >
+struct WrapNativeFallback<T, true >
+{
+  static inline JSObject* Wrap(JSContext* cx, T* parent, nsWrapperCache* cache)
+  {
+    return WrapNativeISupports(cx, parent, cache);
+  }
+};
+
+// Wrapping of our native parent, for cases when it's a WebIDL object (though
+// possibly preffed off).
+template<typename T, bool hasWrapObject=NativeHasMember<T>::WrapObject>
+struct WrapNativeHelper
+{
+  static inline JSObject* Wrap(JSContext* cx, T* parent, nsWrapperCache* cache)
+  {
+    MOZ_ASSERT(cache);
+
+    JSObject* obj;
+    if ((obj = cache->GetWrapper())) {
+      // GetWrapper always unmarks gray.
+      MOZ_ASSERT(!JS::ObjectIsMarkedGray(obj));
+      return obj;
+    }
+
+    // Inline this here while we have non-dom objects in wrapper caches.
+    if (!CouldBeDOMBinding(parent)) {
+      // WrapNativeFallback never returns a gray thing.
+      obj = WrapNativeFallback<T>::Wrap(cx, parent, cache);
+      MOZ_ASSERT_IF(obj, !JS::ObjectIsMarkedGray(obj));
+    } else {
+      // WrapObject never returns a gray thing.
+      obj = parent->WrapObject(cx, nullptr);
+      MOZ_ASSERT_IF(obj, !JS::ObjectIsMarkedGray(obj));
+    }
+
+    return obj;
+  }
+};
+
+// Wrapping of our native parent, for cases when it's not a WebIDL object.  In
+// this case it must be nsISupports.
+template<typename T>
+struct WrapNativeHelper<T, false>
+{
+  static inline JSObject* Wrap(JSContext* cx, T* parent, nsWrapperCache* cache)
+  {
+    JSObject* obj;
+    if (cache && (obj = cache->GetWrapper())) {
+#ifdef DEBUG
+      JS::Rooted<JSObject*> rootedObj(cx, obj);
+      NS_ASSERTION(WrapNativeISupports(cx, parent, cache) == rootedObj,
+                   "Unexpected object in nsWrapperCache");
+      obj = rootedObj;
+#endif
+      MOZ_ASSERT(!JS::ObjectIsMarkedGray(obj));
+      return obj;
+    }
+
+    obj = WrapNativeISupports(cx, parent, cache);
+    MOZ_ASSERT_IF(obj, !JS::ObjectIsMarkedGray(obj));
+    return obj;
+  }
+};
+
+// Finding the associated global for an object.
+template<typename T>
+static inline JSObject*
+FindAssociatedGlobal(JSContext* cx, T* p, nsWrapperCache* cache,
+                     bool useXBLScope = false)
+{
+  if (!p) {
+    return JS::CurrentGlobalOrNull(cx);
+  }
+
+  JSObject* obj = WrapNativeHelper<T>::Wrap(cx, p, cache);
+  if (!obj) {
+    return nullptr;
+  }
+  MOZ_ASSERT(!JS::ObjectIsMarkedGray(obj));
+
+  obj = js::GetGlobalForObjectCrossCompartment(obj);
+
+  if (!useXBLScope) {
+    return obj;
+  }
+
+  // If useXBLScope is true, it means that the canonical reflector for this
+  // native object should live in the content XBL scope. Note that we never put
+  // anonymous content inside an add-on scope.
+  if (xpc::IsInContentXBLScope(obj)) {
+    return obj;
+  }
+  JS::Rooted<JSObject*> rootedObj(cx, obj);
+  JSObject* xblScope = xpc::GetXBLScope(cx, rootedObj);
+  MOZ_ASSERT_IF(xblScope, JS_IsGlobalObject(xblScope));
+  MOZ_ASSERT_IF(xblScope, !JS::ObjectIsMarkedGray(xblScope));
+  return xblScope;
+}
+
+// Finding of the associated global for an object, when we don't want to
+// explicitly pass in things like the nsWrapperCache for it.
+template<typename T>
+static inline JSObject*
+FindAssociatedGlobal(JSContext* cx, const T& p)
+{
+  return FindAssociatedGlobal(cx, GetParentPointer(p), GetWrapperCache(p), GetUseXBLScope(p));
+}
+
+// Specialization for the case of nsIGlobalObject, since in that case
+// we can just get the JSObject* directly.
+template<>
+inline JSObject*
+FindAssociatedGlobal(JSContext* cx, nsIGlobalObject* const& p)
+{
+  if (!p) {
+    return JS::CurrentGlobalOrNull(cx);
+  }
+
+  JSObject* global = p->GetGlobalJSObject();
+  if (!global) {
+    return nullptr;
+  }
+
+  MOZ_ASSERT(JS_IsGlobalObject(global));
+  // This object could be gray if the nsIGlobalObject is the only thing keeping
+  // it alive.
+  JS::ExposeObjectToActiveJS(global);
+  return global;
+}
+
+template<typename T,
+         bool hasAssociatedGlobal=NativeHasMember<T>::GetParentObject>
+struct FindAssociatedGlobalForNative
+{
+  static JSObject* Get(JSContext* cx, JS::Handle<JSObject*> obj)
+  {
+    MOZ_ASSERT(js::IsObjectInContextCompartment(obj, cx));
+    T* native = UnwrapDOMObject<T>(obj);
+    return FindAssociatedGlobal(cx, native->GetParentObject());
+  }
+};
+
+template<typename T>
+struct FindAssociatedGlobalForNative<T, false>
+{
+  static JSObject* Get(JSContext* cx, JS::Handle<JSObject*> obj)
+  {
+    MOZ_CRASH();
+    return nullptr;
+  }
+};
+
+// Helper for calling GetOrCreateDOMReflector with smart pointers
+// (nsAutoPtr/nsRefPtr/nsCOMPtr) or references.
+template <class T, bool isSmartPtr=IsSmartPtr<T>::value>
+struct GetOrCreateDOMReflectorHelper
+{
+  static inline bool GetOrCreate(JSContext* cx, const T& value,
+                                 JS::Handle<JSObject*> givenProto,
+                                 JS::MutableHandle<JS::Value> rval)
+  {
+    return GetOrCreateDOMReflector(cx, value.get(), rval, givenProto);
+  }
+};
+
+template <class T>
+struct GetOrCreateDOMReflectorHelper<T, false>
+{
+  static inline bool GetOrCreate(JSContext* cx, T& value,
+                                 JS::Handle<JSObject*> givenProto,
+                                 JS::MutableHandle<JS::Value> rval)
+  {
+    static_assert(IsRefcounted<T>::value, "Don't pass owned classes in here.");
+    return GetOrCreateDOMReflector(cx, &value, rval, givenProto);
+  }
+};
+
+template<class T>
+inline bool
+GetOrCreateDOMReflector(JSContext* cx, T& value,
+                        JS::MutableHandle<JS::Value> rval,
+                        JS::Handle<JSObject*> givenProto = nullptr)
+{
+  return GetOrCreateDOMReflectorHelper<T>::GetOrCreate(cx, value, givenProto,
+                                                       rval);
+}
+
+// Helper for calling GetOrCreateDOMReflectorNoWrap with smart pointers
+// (nsAutoPtr/nsRefPtr/nsCOMPtr) or references.
+template <class T, bool isSmartPtr=IsSmartPtr<T>::value>
+struct GetOrCreateDOMReflectorNoWrapHelper
+{
+  static inline bool GetOrCreate(JSContext* cx, const T& value,
+                                 JS::MutableHandle<JS::Value> rval)
+  {
+    return GetOrCreateDOMReflectorNoWrap(cx, value.get(), rval);
+  }
+};
+
+template <class T>
+struct GetOrCreateDOMReflectorNoWrapHelper<T, false>
+{
+  static inline bool GetOrCreate(JSContext* cx, T& value,
+                                 JS::MutableHandle<JS::Value> rval)
+  {
+    return GetOrCreateDOMReflectorNoWrap(cx, &value, rval);
+  }
+};
+
+template<class T>
+inline bool
+GetOrCreateDOMReflectorNoWrap(JSContext* cx, T& value,
+                              JS::MutableHandle<JS::Value> rval)
+{
+  return
+    GetOrCreateDOMReflectorNoWrapHelper<T>::GetOrCreate(cx, value, rval);
+}
+
+template <class T>
+inline JSObject*
+GetCallbackFromCallbackObject(T* aObj)
+{
+  return aObj->Callback();
+}
+
+// Helper for getting the callback JSObject* of a smart ptr around a
+// CallbackObject or a reference to a CallbackObject or something like
+// that.
+template <class T, bool isSmartPtr=IsSmartPtr<T>::value>
+struct GetCallbackFromCallbackObjectHelper
+{
+  static inline JSObject* Get(const T& aObj)
+  {
+    return GetCallbackFromCallbackObject(aObj.get());
+  }
+};
+
+template <class T>
+struct GetCallbackFromCallbackObjectHelper<T, false>
+{
+  static inline JSObject* Get(T& aObj)
+  {
+    return GetCallbackFromCallbackObject(&aObj);
+  }
+};
+
+template<class T>
+inline JSObject*
+GetCallbackFromCallbackObject(T& aObj)
+{
+  return GetCallbackFromCallbackObjectHelper<T>::Get(aObj);
+}
+
+static inline bool
+AtomizeAndPinJSString(JSContext* cx, jsid& id, const char* chars)
+{
+  if (JSString *str = ::JS_AtomizeAndPinString(cx, chars)) {
+    id = INTERNED_STRING_TO_JSID(cx, str);
+    return true;
+  }
+  return false;
+}
+
+// Spec needs a name property
+template <typename Spec>
+static bool
+InitIds(JSContext* cx, const Prefable<Spec>* prefableSpecs, jsid* ids)
+{
+  MOZ_ASSERT(prefableSpecs);
+  MOZ_ASSERT(prefableSpecs->specs);
+  do {
+    // We ignore whether the set of ids is enabled and just intern all the IDs,
+    // because this is only done once per application runtime.
+    Spec* spec = prefableSpecs->specs;
+    do {
+      if (!JS::PropertySpecNameToPermanentId(cx, spec->name, ids)) {
+        return false;
+      }
+    } while (++ids, (++spec)->name);
+
+    // We ran out of ids for that pref.  Put a JSID_VOID in on the id
+    // corresponding to the list terminator for the pref.
+    *ids = JSID_VOID;
+    ++ids;
+  } while ((++prefableSpecs)->specs);
+
+  return true;
+}
+
+bool
+QueryInterface(JSContext* cx, unsigned argc, JS::Value* vp);
+
+template <class T>
+struct
+WantsQueryInterface
+{
+  static_assert(IsBaseOf<nsISupports, T>::value,
+                "QueryInterface can't work without an nsISupports.");
+  static bool Enabled(JSContext* aCx, JSObject* aGlobal)
+  {
+    return NS_IsMainThread() && IsChromeOrXBL(aCx, aGlobal);
+  }
+};
+
+void
+GetInterfaceImpl(JSContext* aCx, nsIInterfaceRequestor* aRequestor,
+                 nsWrapperCache* aCache, nsIJSID* aIID,
+                 JS::MutableHandle<JS::Value> aRetval, ErrorResult& aError);
+
+template<class T>
+void
+GetInterface(JSContext* aCx, T* aThis, nsIJSID* aIID,
+             JS::MutableHandle<JS::Value> aRetval, ErrorResult& aError)
+{
+  GetInterfaceImpl(aCx, aThis, aThis, aIID, aRetval, aError);
+}
+
+bool
+UnforgeableValueOf(JSContext* cx, unsigned argc, JS::Value* vp);
+
+bool
+ThrowingConstructor(JSContext* cx, unsigned argc, JS::Value* vp);
+
+bool
+ThrowConstructorWithoutNew(JSContext* cx, const char* name);
+
+bool
+GetPropertyOnPrototype(JSContext* cx, JS::Handle<JSObject*> proxy,
+                       JS::Handle<JS::Value> receiver, JS::Handle<jsid> id,
+                       bool* found, JS::MutableHandle<JS::Value> vp);
+
+//
+bool
+HasPropertyOnPrototype(JSContext* cx, JS::Handle<JSObject*> proxy,
+                       JS::Handle<jsid> id, bool* has);
+
+
+// Append the property names in "names" to "props". If
+// shadowPrototypeProperties is false then skip properties that are also
+// present on the proto chain of proxy.  If shadowPrototypeProperties is true,
+// then the "proxy" argument is ignored.
+bool
+AppendNamedPropertyIds(JSContext* cx, JS::Handle<JSObject*> proxy,
+                       nsTArray<nsString>& names,
+                       bool shadowPrototypeProperties, JS::AutoIdVector& props);
+
+namespace binding_detail {
+
+class FastErrorResult :
+    public mozilla::binding_danger::TErrorResult<
+      mozilla::binding_danger::JustAssertCleanupPolicy>
+{
+};
+
+} // namespace binding_detail
+
+enum StringificationBehavior {
+  eStringify,
+  eEmpty,
+  eNull
+};
+
+template<typename T>
+static inline bool
+ConvertJSValueToString(JSContext* cx, JS::Handle<JS::Value> v,
+                       StringificationBehavior nullBehavior,
+                       StringificationBehavior undefinedBehavior,
+                       T& result)
+{
+  JSString *s;
+  if (v.isString()) {
+    s = v.toString();
+  } else {
+    StringificationBehavior behavior;
+    if (v.isNull()) {
+      behavior = nullBehavior;
+    } else if (v.isUndefined()) {
+      behavior = undefinedBehavior;
+    } else {
+      behavior = eStringify;
+    }
+
+    if (behavior != eStringify) {
+      if (behavior == eEmpty) {
+        result.Truncate();
+      } else {
+        result.SetIsVoid(true);
+      }
+      return true;
+    }
+
+    s = JS::ToString(cx, v);
+    if (!s) {
+      return false;
+    }
+  }
+
+  return AssignJSString(cx, result, s);
+}
+
+void
+NormalizeUSVString(JSContext* aCx, nsAString& aString);
+
+void
+NormalizeUSVString(JSContext* aCx, binding_detail::FakeString& aString);
+
+template<typename T>
+inline bool
+ConvertIdToString(JSContext* cx, JS::HandleId id, T& result, bool& isSymbol)
+{
+  if (MOZ_LIKELY(JSID_IS_STRING(id))) {
+    if (!AssignJSString(cx, result, JSID_TO_STRING(id))) {
+      return false;
+    }
+  } else if (JSID_IS_SYMBOL(id)) {
+    isSymbol = true;
+    return true;
+  } else {
+    JS::RootedValue nameVal(cx, js::IdToValue(id));
+    if (!ConvertJSValueToString(cx, nameVal, eStringify, eStringify, result)) {
+      return false;
+    }
+  }
+  isSymbol = false;
+  return true;
+}
+
+bool
+ConvertJSValueToByteString(JSContext* cx, JS::Handle<JS::Value> v,
+                           bool nullable, nsACString& result);
+
+template<typename T>
+void DoTraceSequence(JSTracer* trc, FallibleTArray<T>& seq);
+template<typename T>
+void DoTraceSequence(JSTracer* trc, InfallibleTArray<T>& seq);
+
+// Class used to trace sequences, with specializations for various
+// sequence types.
+template<typename T,
+         bool isDictionary=IsBaseOf<DictionaryBase, T>::value,
+         bool isTypedArray=IsBaseOf<AllTypedArraysBase, T>::value,
+         bool isOwningUnion=IsBaseOf<AllOwningUnionBase, T>::value>
+class SequenceTracer
+{
+  explicit SequenceTracer() = delete; // Should never be instantiated
+};
+
+// sequence<object> or sequence<object?>
+template<>
+class SequenceTracer<JSObject*, false, false, false>
+{
+  explicit SequenceTracer() = delete; // Should never be instantiated
+
+public:
+  static void TraceSequence(JSTracer* trc, JSObject** objp, JSObject** end) {
+    for (; objp != end; ++objp) {
+      JS::UnsafeTraceRoot(trc, objp, "sequence<object>");
+    }
+  }
+};
+
+// sequence<any>
+template<>
+class SequenceTracer<JS::Value, false, false, false>
+{
+  explicit SequenceTracer() = delete; // Should never be instantiated
+
+public:
+  static void TraceSequence(JSTracer* trc, JS::Value* valp, JS::Value* end) {
+    for (; valp != end; ++valp) {
+      JS::UnsafeTraceRoot(trc, valp, "sequence<any>");
+    }
+  }
+};
+
+// sequence<sequence<T>>
+template<typename T>
+class SequenceTracer<Sequence<T>, false, false, false>
+{
+  explicit SequenceTracer() = delete; // Should never be instantiated
+
+public:
+  static void TraceSequence(JSTracer* trc, Sequence<T>* seqp, Sequence<T>* end) {
+    for (; seqp != end; ++seqp) {
+      DoTraceSequence(trc, *seqp);
+    }
+  }
+};
+
+// sequence<sequence<T>> as return value
+template<typename T>
+class SequenceTracer<nsTArray<T>, false, false, false>
+{
+  explicit SequenceTracer() = delete; // Should never be instantiated
+
+public:
+  static void TraceSequence(JSTracer* trc, nsTArray<T>* seqp, nsTArray<T>* end) {
+    for (; seqp != end; ++seqp) {
+      DoTraceSequence(trc, *seqp);
+    }
+  }
+};
+
+// sequence<someDictionary>
+template<typename T>
+class SequenceTracer<T, true, false, false>
+{
+  explicit SequenceTracer() = delete; // Should never be instantiated
+
+public:
+  static void TraceSequence(JSTracer* trc, T* dictp, T* end) {
+    for (; dictp != end; ++dictp) {
+      dictp->TraceDictionary(trc);
+    }
+  }
+};
+
+// sequence<SomeTypedArray>
+template<typename T>
+class SequenceTracer<T, false, true, false>
+{
+  explicit SequenceTracer() = delete; // Should never be instantiated
+
+public:
+  static void TraceSequence(JSTracer* trc, T* arrayp, T* end) {
+    for (; arrayp != end; ++arrayp) {
+      arrayp->TraceSelf(trc);
+    }
+  }
+};
+
+// sequence<SomeOwningUnion>
+template<typename T>
+class SequenceTracer<T, false, false, true>
+{
+  explicit SequenceTracer() = delete; // Should never be instantiated
+
+public:
+  static void TraceSequence(JSTracer* trc, T* arrayp, T* end) {
+    for (; arrayp != end; ++arrayp) {
+      arrayp->TraceUnion(trc);
+    }
+  }
+};
+
+// sequence<T?> with T? being a Nullable<T>
+template<typename T>
+class SequenceTracer<Nullable<T>, false, false, false>
+{
+  explicit SequenceTracer() = delete; // Should never be instantiated
+
+public:
+  static void TraceSequence(JSTracer* trc, Nullable<T>* seqp,
+                            Nullable<T>* end) {
+    for (; seqp != end; ++seqp) {
+      if (!seqp->IsNull()) {
+        // Pretend like we actually have a length-one sequence here so
+        // we can do template instantiation correctly for T.
+        T& val = seqp->Value();
+        T* ptr = &val;
+        SequenceTracer<T>::TraceSequence(trc, ptr, ptr+1);
+      }
+    }
+  }
+};
+
+template<typename T>
+static void
+TraceMozMapValue(T* aValue, void* aClosure)
+{
+  JSTracer* trc = static_cast<JSTracer*>(aClosure);
+  // Act like it's a one-element sequence to leverage all that infrastructure.
+  SequenceTracer<T>::TraceSequence(trc, aValue, aValue + 1);
+}
+
+template<typename T>
+void TraceMozMap(JSTracer* trc, MozMap<T>& map)
+{
+  map.EnumerateValues(TraceMozMapValue<T>, trc);
+}
+
+// sequence<MozMap>
+template<typename T>
+class SequenceTracer<MozMap<T>, false, false, false>
+{
+  explicit SequenceTracer() = delete; // Should never be instantiated
+
+public:
+  static void TraceSequence(JSTracer* trc, MozMap<T>* seqp, MozMap<T>* end) {
+    for (; seqp != end; ++seqp) {
+      seqp->EnumerateValues(TraceMozMapValue<T>, trc);
+    }
+  }
+};
+
+template<typename T>
+void DoTraceSequence(JSTracer* trc, FallibleTArray<T>& seq)
+{
+  SequenceTracer<T>::TraceSequence(trc, seq.Elements(),
+                                   seq.Elements() + seq.Length());
+}
+
+template<typename T>
+void DoTraceSequence(JSTracer* trc, InfallibleTArray<T>& seq)
+{
+  SequenceTracer<T>::TraceSequence(trc, seq.Elements(),
+                                   seq.Elements() + seq.Length());
+}
+
+// Rooter class for sequences; this is what we mostly use in the codegen
+template<typename T>
+class MOZ_RAII SequenceRooter final : private JS::CustomAutoRooter
+{
+public:
+  SequenceRooter(JSContext *aCx, FallibleTArray<T>* aSequence
+                 MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+    : JS::CustomAutoRooter(aCx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT),
+      mFallibleArray(aSequence),
+      mSequenceType(eFallibleArray)
+  {
+  }
+
+  SequenceRooter(JSContext *aCx, InfallibleTArray<T>* aSequence
+                 MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+    : JS::CustomAutoRooter(aCx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT),
+      mInfallibleArray(aSequence),
+      mSequenceType(eInfallibleArray)
+  {
+  }
+
+  SequenceRooter(JSContext *aCx, Nullable<nsTArray<T> >* aSequence
+                 MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+    : JS::CustomAutoRooter(aCx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT),
+      mNullableArray(aSequence),
+      mSequenceType(eNullableArray)
+  {
+  }
+
+ private:
+  enum SequenceType {
+    eInfallibleArray,
+    eFallibleArray,
+    eNullableArray
+  };
+
+  virtual void trace(JSTracer *trc) override
+  {
+    if (mSequenceType == eFallibleArray) {
+      DoTraceSequence(trc, *mFallibleArray);
+    } else if (mSequenceType == eInfallibleArray) {
+      DoTraceSequence(trc, *mInfallibleArray);
+    } else {
+      MOZ_ASSERT(mSequenceType == eNullableArray);
+      if (!mNullableArray->IsNull()) {
+        DoTraceSequence(trc, mNullableArray->Value());
+      }
+    }
+  }
+
+  union {
+    InfallibleTArray<T>* mInfallibleArray;
+    FallibleTArray<T>* mFallibleArray;
+    Nullable<nsTArray<T> >* mNullableArray;
+  };
+
+  SequenceType mSequenceType;
+};
+
+// Rooter class for MozMap; this is what we mostly use in the codegen.
+template<typename T>
+class MOZ_RAII MozMapRooter final : private JS::CustomAutoRooter
+{
+public:
+  MozMapRooter(JSContext *aCx, MozMap<T>* aMozMap
+               MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+    : JS::CustomAutoRooter(aCx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT),
+      mMozMap(aMozMap),
+      mMozMapType(eMozMap)
+  {
+  }
+
+  MozMapRooter(JSContext *aCx, Nullable<MozMap<T>>* aMozMap
+                 MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+    : JS::CustomAutoRooter(aCx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT),
+      mNullableMozMap(aMozMap),
+      mMozMapType(eNullableMozMap)
+  {
+  }
+
+private:
+  enum MozMapType {
+    eMozMap,
+    eNullableMozMap
+  };
+
+  virtual void trace(JSTracer *trc) override
+  {
+    if (mMozMapType == eMozMap) {
+      TraceMozMap(trc, *mMozMap);
+    } else {
+      MOZ_ASSERT(mMozMapType == eNullableMozMap);
+      if (!mNullableMozMap->IsNull()) {
+        TraceMozMap(trc, mNullableMozMap->Value());
+      }
+    }
+  }
+
+  union {
+    MozMap<T>* mMozMap;
+    Nullable<MozMap<T>>* mNullableMozMap;
+  };
+
+  MozMapType mMozMapType;
+};
+
+template<typename T>
+class MOZ_RAII RootedUnion : public T,
+                             private JS::CustomAutoRooter
+{
+public:
+  explicit RootedUnion(JSContext* cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM) :
+    T(),
+    JS::CustomAutoRooter(cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT)
+  {
+  }
+
+  virtual void trace(JSTracer *trc) override
+  {
+    this->TraceUnion(trc);
+  }
+};
+
+template<typename T>
+class MOZ_STACK_CLASS NullableRootedUnion : public Nullable<T>,
+                                            private JS::CustomAutoRooter
+{
+public:
+  explicit NullableRootedUnion(JSContext* cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM) :
+    Nullable<T>(),
+    JS::CustomAutoRooter(cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_TO_PARENT)
+  {
+  }
+
+  virtual void trace(JSTracer *trc) override
+  {
+    if (!this->IsNull()) {
+      this->Value().TraceUnion(trc);
+    }
+  }
+};
+
+inline bool
+IdEquals(jsid id, const char* string)
+{
+  return JSID_IS_STRING(id) &&
+         JS_FlatStringEqualsAscii(JSID_TO_FLAT_STRING(id), string);
+}
+
+inline bool
+AddStringToIDVector(JSContext* cx, JS::AutoIdVector& vector, const char* name)
+{
+  return vector.growBy(1) &&
+         AtomizeAndPinJSString(cx, *(vector[vector.length() - 1]).address(), name);
+}
+
+// We use one constructor JSNative to represent all DOM interface objects (so
+// we can easily detect when we need to wrap them in an Xray wrapper). We store
+// the real JSNative in the mNative member of a JSNativeHolder in the
+// CONSTRUCTOR_NATIVE_HOLDER_RESERVED_SLOT slot of the JSFunction object for a
+// specific interface object. We also store the NativeProperties in the
+// JSNativeHolder.
+// Note that some interface objects are not yet a JSFunction but a normal
+// JSObject with a DOMJSClass, those do not use these slots.
+
+enum {
+  CONSTRUCTOR_NATIVE_HOLDER_RESERVED_SLOT = 0
+};
+
+bool
+Constructor(JSContext* cx, unsigned argc, JS::Value* vp);
+
+// Implementation of the bits that XrayWrapper needs
+
+/**
+ * This resolves operations, attributes and constants of the interfaces for obj.
+ *
+ * wrapper is the Xray JS object.
+ * obj is the target object of the Xray, a binding's instance object or a
+ *     interface or interface prototype object.
+ */
+bool
+XrayResolveOwnProperty(JSContext* cx, JS::Handle<JSObject*> wrapper,
+                       JS::Handle<JSObject*> obj,
+                       JS::Handle<jsid> id,
+                       JS::MutableHandle<JS::PropertyDescriptor> desc,
+                       bool& cacheOnHolder);
+
+/**
+ * Define a property on obj through an Xray wrapper.
+ *
+ * wrapper is the Xray JS object.
+ * obj is the target object of the Xray, a binding's instance object or a
+ *     interface or interface prototype object.
+ * id and desc are the parameters for the property to be defined.
+ * result is the out-parameter indicating success (read it only if
+ *     this returns true and also sets *defined to true).
+ * defined will be set to true if a property was set as a result of this call.
+ */
+bool
+XrayDefineProperty(JSContext* cx, JS::Handle<JSObject*> wrapper,
+                   JS::Handle<JSObject*> obj, JS::Handle<jsid> id,
+                   JS::Handle<JS::PropertyDescriptor> desc,
+                   JS::ObjectOpResult &result,
+                   bool *defined);
+
+/**
+ * Add to props the property keys of all indexed or named properties of obj and
+ * operations, attributes and constants of the interfaces for obj.
+ *
+ * wrapper is the Xray JS object.
+ * obj is the target object of the Xray, a binding's instance object or a
+ *     interface or interface prototype object.
+ * flags are JSITER_* flags.
+ */
+bool
+XrayOwnPropertyKeys(JSContext* cx, JS::Handle<JSObject*> wrapper,
+                    JS::Handle<JSObject*> obj,
+                    unsigned flags, JS::AutoIdVector& props);
+
+/**
+ * Returns the prototype to use for an Xray for a DOM object, wrapped in cx's
+ * compartment. This always returns the prototype that would be used for a DOM
+ * object if we ignore any changes that might have been done to the prototype
+ * chain by JS, the XBL code or plugins.
+ *
+ * cx should be in the Xray's compartment.
+ * obj is the target object of the Xray, a binding's instance object or an
+ *     interface or interface prototype object.
+ */
+inline bool
+XrayGetNativeProto(JSContext* cx, JS::Handle<JSObject*> obj,
+                   JS::MutableHandle<JSObject*> protop)
+{
+  JS::Rooted<JSObject*> global(cx, js::GetGlobalForObjectCrossCompartment(obj));
+  {
+    JSAutoCompartment ac(cx, global);
+    const DOMJSClass* domClass = GetDOMClass(obj);
+    if (domClass) {
+      ProtoHandleGetter protoGetter = domClass->mGetProto;
+      if (protoGetter) {
+        protop.set(protoGetter(cx));
+      } else {
+        protop.set(JS::GetRealmObjectPrototype(cx));
+      }
+    } else if (JS_ObjectIsFunction(cx, obj)) {
+      MOZ_ASSERT(JS_IsNativeFunction(obj, Constructor));
+      protop.set(JS::GetRealmFunctionPrototype(cx));
+    } else {
+      const js::Class* clasp = js::GetObjectClass(obj);
+      MOZ_ASSERT(IsDOMIfaceAndProtoClass(clasp));
+      ProtoGetter protoGetter =
+        DOMIfaceAndProtoJSClass::FromJSClass(clasp)->mGetParentProto;
+      protop.set(protoGetter(cx));
+    }
+  }
+
+  return JS_WrapObject(cx, protop);
+}
+
+/**
+ * Get the Xray expando class to use for the given DOM object.
+ */
+const JSClass*
+XrayGetExpandoClass(JSContext* cx, JS::Handle<JSObject*> obj);
+
+/**
+ * Delete a named property, if any.  Return value is false if exception thrown,
+ * true otherwise.  The caller should not do any more work after calling this
+ * function, because it has no way whether a deletion was performed and hence
+ * opresult already has state set on it.  If callers ever need to change that,
+ * add a "bool* found" argument and change the generated DeleteNamedProperty to
+ * use it instead of a local variable.
+ */
+bool
+XrayDeleteNamedProperty(JSContext* cx, JS::Handle<JSObject*> wrapper,
+                        JS::Handle<JSObject*> obj, JS::Handle<jsid> id,
+                        JS::ObjectOpResult& opresult);
+
+/**
+ * Get the object which should be used to cache the return value of a property
+ * getter in the case of a [Cached] or [StoreInSlot] property.  `obj` is the
+ * `this` value for our property getter that we're working with.
+ *
+ * This function can return null on failure to allocate the object, throwing on
+ * the JSContext in the process.
+ *
+ * The isXray outparam will be set to true if obj is an Xray and false
+ * otherwise.
+ *
+ * Note that the Slow version should only be called from
+ * GetCachedSlotStorageObject.
+ */
+JSObject*
+GetCachedSlotStorageObjectSlow(JSContext* cx, JS::Handle<JSObject*> obj,
+                               bool* isXray);
+
+inline JSObject*
+GetCachedSlotStorageObject(JSContext* cx, JS::Handle<JSObject*> obj,
+                           bool* isXray) {
+  if (IsDOMObject(obj)) {
+    *isXray = false;
+    return obj;
+  }
+
+  return GetCachedSlotStorageObjectSlow(cx, obj, isXray);
+}
+
+extern NativePropertyHooks sEmptyNativePropertyHooks;
+
+extern const js::ClassOps sBoringInterfaceObjectClassClassOps;
+
+extern const js::ObjectOps sInterfaceObjectClassObjectOps;
+
+inline bool
+UseDOMXray(JSObject* obj)
+{
+  const js::Class* clasp = js::GetObjectClass(obj);
+  return IsDOMClass(clasp) ||
+         JS_IsNativeFunction(obj, Constructor) ||
+         IsDOMIfaceAndProtoClass(clasp);
+}
+
+#ifdef DEBUG
+inline bool
+HasConstructor(JSObject* obj)
+{
+  return JS_IsNativeFunction(obj, Constructor) ||
+         js::GetObjectClass(obj)->getConstruct();
+}
+#endif
+
+// Helpers for creating a const version of a type.
+template<typename T>
+const T& Constify(T& arg)
+{
+  return arg;
+}
+
+// Helper for turning (Owning)NonNull<T> into T&
+template<typename T>
+T& NonNullHelper(T& aArg)
+{
+  return aArg;
+}
+
+template<typename T>
+T& NonNullHelper(NonNull<T>& aArg)
+{
+  return aArg;
+}
+
+template<typename T>
+const T& NonNullHelper(const NonNull<T>& aArg)
+{
+  return aArg;
+}
+
+template<typename T>
+T& NonNullHelper(OwningNonNull<T>& aArg)
+{
+  return aArg;
+}
+
+template<typename T>
+const T& NonNullHelper(const OwningNonNull<T>& aArg)
+{
+  return aArg;
+}
+
+inline
+void NonNullHelper(NonNull<binding_detail::FakeString>& aArg)
+{
+  // This overload is here to make sure that we never end up applying
+  // NonNullHelper to a NonNull<binding_detail::FakeString>. If we
+  // try to, it should fail to compile, since presumably the caller will try to
+  // use our nonexistent return value.
+}
+
+inline
+void NonNullHelper(const NonNull<binding_detail::FakeString>& aArg)
+{
+  // This overload is here to make sure that we never end up applying
+  // NonNullHelper to a NonNull<binding_detail::FakeString>. If we
+  // try to, it should fail to compile, since presumably the caller will try to
+  // use our nonexistent return value.
+}
+
+inline
+void NonNullHelper(binding_detail::FakeString& aArg)
+{
+  // This overload is here to make sure that we never end up applying
+  // NonNullHelper to a FakeString before we've constified it.  If we
+  // try to, it should fail to compile, since presumably the caller will try to
+  // use our nonexistent return value.
+}
+
+MOZ_ALWAYS_INLINE
+const nsAString& NonNullHelper(const binding_detail::FakeString& aArg)
+{
+  return aArg;
+}
+
+// Reparent the wrapper of aObj to whatever its native now thinks its
+// parent should be.
+nsresult
+ReparentWrapper(JSContext* aCx, JS::Handle<JSObject*> aObj);
+
+/**
+ * Used to implement the Symbol.hasInstance property of an interface object.
+ */
+bool
+InterfaceHasInstance(JSContext* cx, unsigned argc, JS::Value* vp);
+
+bool
+InterfaceHasInstance(JSContext* cx, int prototypeID, int depth,
+                     JS::Handle<JSObject*> instance,
+                     bool* bp);
+
+// Helper for lenient getters/setters to report to console.  If this
+// returns false, we couldn't even get a global.
+bool
+ReportLenientThisUnwrappingFailure(JSContext* cx, JSObject* obj);
+
+// Given a JSObject* that represents the chrome side of a JS-implemented WebIDL
+// interface, get the nsIGlobalObject corresponding to the content side, if any.
+// A false return means an exception was thrown.
+bool
+GetContentGlobalForJSImplementedObject(JSContext* cx, JS::Handle<JSObject*> obj,
+                                       nsIGlobalObject** global);
+
+void
+ConstructJSImplementation(const char* aContractId,
+                          nsIGlobalObject* aGlobal,
+                          JS::MutableHandle<JSObject*> aObject,
+                          ErrorResult& aRv);
+
+already_AddRefed<nsIGlobalObject>
+ConstructJSImplementation(const char* aContractId,
+                          const GlobalObject& aGlobal,
+                          JS::MutableHandle<JSObject*> aObject,
+                          ErrorResult& aRv);
+
+/**
+ * Convert an nsCString to jsval, returning true on success.
+ * These functions are intended for ByteString implementations.
+ * As such, the string is not UTF-8 encoded.  Any UTF8 strings passed to these
+ * methods will be mangled.
+ */
+bool NonVoidByteStringToJsval(JSContext *cx, const nsACString &str,
+                              JS::MutableHandle<JS::Value> rval);
+inline bool ByteStringToJsval(JSContext *cx, const nsACString &str,
+                              JS::MutableHandle<JS::Value> rval)
+{
+    if (str.IsVoid()) {
+        rval.setNull();
+        return true;
+    }
+    return NonVoidByteStringToJsval(cx, str, rval);
+}
+
+template<class T, bool isISupports=IsBaseOf<nsISupports, T>::value>
+struct PreserveWrapperHelper
+{
+  static void PreserveWrapper(T* aObject)
+  {
+    aObject->PreserveWrapper(aObject, NS_CYCLE_COLLECTION_PARTICIPANT(T));
+  }
+};
+
+template<class T>
+struct PreserveWrapperHelper<T, true>
+{
+  static void PreserveWrapper(T* aObject)
+  {
+    aObject->PreserveWrapper(reinterpret_cast<nsISupports*>(aObject));
+  }
+};
+
+template<class T>
+void PreserveWrapper(T* aObject)
+{
+  PreserveWrapperHelper<T>::PreserveWrapper(aObject);
+}
+
+template<class T, bool isISupports=IsBaseOf<nsISupports, T>::value>
+struct CastingAssertions
+{
+  static bool ToSupportsIsCorrect(T*)
+  {
+    return true;
+  }
+  static bool ToSupportsIsOnPrimaryInheritanceChain(T*, nsWrapperCache*)
+  {
+    return true;
+  }
+};
+
+template<class T>
+struct CastingAssertions<T, true>
+{
+  static bool ToSupportsIsCorrect(T* aObject)
+  {
+    return ToSupports(aObject) ==  reinterpret_cast<nsISupports*>(aObject);
+  }
+  static bool ToSupportsIsOnPrimaryInheritanceChain(T* aObject,
+                                                    nsWrapperCache* aCache)
+  {
+    return reinterpret_cast<void*>(aObject) != aCache;
+  }
+};
+
+template<class T>
+bool
+ToSupportsIsCorrect(T* aObject)
+{
+  return CastingAssertions<T>::ToSupportsIsCorrect(aObject);
+}
+
+template<class T>
+bool
+ToSupportsIsOnPrimaryInheritanceChain(T* aObject, nsWrapperCache* aCache)
+{
+  return CastingAssertions<T>::ToSupportsIsOnPrimaryInheritanceChain(aObject,
+                                                                     aCache);
+}
+
+// The BindingJSObjectCreator class is supposed to be used by a caller that
+// wants to create and initialise a binding JSObject. After initialisation has
+// been successfully completed it should call ForgetObject().
+// The BindingJSObjectCreator object will root the JSObject until ForgetObject()
+// is called on it. If the native object for the binding is refcounted it will
+// also hold a strong reference to it, that reference is transferred to the
+// JSObject (which holds the native in a slot) when ForgetObject() is called. If
+// the BindingJSObjectCreator object is destroyed and ForgetObject() was never
+// called on it then the JSObject's slot holding the native will be set to
+// undefined, and for a refcounted native the strong reference will be released.
+template<class T>
+class MOZ_STACK_CLASS BindingJSObjectCreator
+{
+public:
+  explicit BindingJSObjectCreator(JSContext* aCx)
+    : mReflector(aCx)
+  {
+  }
+
+  ~BindingJSObjectCreator()
+  {
+    if (mReflector) {
+      js::SetReservedOrProxyPrivateSlot(mReflector, DOM_OBJECT_SLOT,
+                                        JS::UndefinedValue());
+    }
+  }
+
+  void
+  CreateProxyObject(JSContext* aCx, const js::Class* aClass,
+                    const DOMProxyHandler* aHandler,
+                    JS::Handle<JSObject*> aProto, T* aNative,
+                    JS::MutableHandle<JSObject*> aReflector)
+  {
+    js::ProxyOptions options;
+    options.setClass(aClass);
+    JS::Rooted<JS::Value> proxyPrivateVal(aCx, JS::PrivateValue(aNative));
+    aReflector.set(js::NewProxyObject(aCx, aHandler, proxyPrivateVal, aProto,
+                                      options));
+    if (aReflector) {
+      mNative = aNative;
+      mReflector = aReflector;
+    }
+  }
+
+  void
+  CreateObject(JSContext* aCx, const JSClass* aClass,
+               JS::Handle<JSObject*> aProto,
+               T* aNative, JS::MutableHandle<JSObject*> aReflector)
+  {
+    aReflector.set(JS_NewObjectWithGivenProto(aCx, aClass, aProto));
+    if (aReflector) {
+      js::SetReservedSlot(aReflector, DOM_OBJECT_SLOT, JS::PrivateValue(aNative));
+      mNative = aNative;
+      mReflector = aReflector;
+    }
+  }
+
+  void
+  InitializationSucceeded()
+  {
+    void* dummy;
+    mNative.forget(&dummy);
+    mReflector = nullptr;
+  }
+
+private:
+  struct OwnedNative
+  {
+    // Make sure the native objects inherit from NonRefcountedDOMObject so
+    // that we log their ctor and dtor.
+    static_assert(IsBaseOf<NonRefcountedDOMObject, T>::value,
+                  "Non-refcounted objects with DOM bindings should inherit "
+                  "from NonRefcountedDOMObject.");
+
+    OwnedNative&
+    operator=(T* aNative)
+    {
+      return *this;
+    }
+
+    // This signature sucks, but it's the only one that will make a nsRefPtr
+    // just forget about its pointer without warning.
+    void
+    forget(void**)
+    {
+    }
+  };
+
+  JS::Rooted<JSObject*> mReflector;
+  typename Conditional<IsRefcounted<T>::value, RefPtr<T>, OwnedNative>::Type mNative;
+};
+
+template<class T>
+struct DeferredFinalizerImpl
+{
+  typedef typename Conditional<IsSame<T, nsISupports>::value,
+                               nsCOMPtr<T>,
+                               typename Conditional<IsRefcounted<T>::value,
+                                                    RefPtr<T>,
+                                                    nsAutoPtr<T>>::Type>::Type SmartPtr;
+  typedef SegmentedVector<SmartPtr> SmartPtrArray;
+
+  static_assert(IsSame<T, nsISupports>::value || !IsBaseOf<nsISupports, T>::value,
+                "nsISupports classes should all use the nsISupports instantiation");
+
+  static inline void
+  AppendAndTake(SegmentedVector<nsCOMPtr<nsISupports>>& smartPtrArray, nsISupports* ptr)
+  {
+    smartPtrArray.InfallibleAppend(dont_AddRef(ptr));
+  }
+  template<class U>
+  static inline void
+  AppendAndTake(SegmentedVector<RefPtr<U>>& smartPtrArray, U* ptr)
+  {
+    smartPtrArray.InfallibleAppend(dont_AddRef(ptr));
+  }
+  template<class U>
+  static inline void
+  AppendAndTake(SegmentedVector<nsAutoPtr<U>>& smartPtrArray, U* ptr)
+  {
+    smartPtrArray.InfallibleAppend(ptr);
+  }
+
+  static void*
+  AppendDeferredFinalizePointer(void* aData, void* aObject)
+  {
+    SmartPtrArray* pointers = static_cast<SmartPtrArray*>(aData);
+    if (!pointers) {
+      pointers = new SmartPtrArray();
+    }
+    AppendAndTake(*pointers, static_cast<T*>(aObject));
+    return pointers;
+  }
+  static bool
+  DeferredFinalize(uint32_t aSlice, void* aData)
+  {
+    MOZ_ASSERT(aSlice > 0, "nonsensical/useless call with aSlice == 0");
+    SmartPtrArray* pointers = static_cast<SmartPtrArray*>(aData);
+    uint32_t oldLen = pointers->Length();
+    if (oldLen < aSlice) {
+      aSlice = oldLen;
+    }
+    uint32_t newLen = oldLen - aSlice;
+    pointers->PopLastN(aSlice);
+    if (newLen == 0) {
+      delete pointers;
+      return true;
+    }
+    return false;
+  }
+};
+
+template<class T,
+         bool isISupports=IsBaseOf<nsISupports, T>::value>
+struct DeferredFinalizer
+{
+  static void
+  AddForDeferredFinalization(T* aObject)
+  {
+    typedef DeferredFinalizerImpl<T> Impl;
+    DeferredFinalize(Impl::AppendDeferredFinalizePointer,
+                     Impl::DeferredFinalize, aObject);
+  }
+};
+
+template<class T>
+struct DeferredFinalizer<T, true>
+{
+  static void
+  AddForDeferredFinalization(T* aObject)
+  {
+    DeferredFinalize(reinterpret_cast<nsISupports*>(aObject));
+  }
+};
+
+template<class T>
+static void
+AddForDeferredFinalization(T* aObject)
+{
+  DeferredFinalizer<T>::AddForDeferredFinalization(aObject);
+}
+
+// This returns T's CC participant if it participates in CC or null if it
+// doesn't. This also returns null for classes that don't inherit from
+// nsISupports (QI should be used to get the participant for those).
+template<class T, bool isISupports=IsBaseOf<nsISupports, T>::value>
+class GetCCParticipant
+{
+  // Helper for GetCCParticipant for classes that participate in CC.
+  template<class U>
+  static constexpr nsCycleCollectionParticipant*
+  GetHelper(int, typename U::NS_CYCLE_COLLECTION_INNERCLASS* dummy=nullptr)
+  {
+    return T::NS_CYCLE_COLLECTION_INNERCLASS::GetParticipant();
+  }
+  // Helper for GetCCParticipant for classes that don't participate in CC.
+  template<class U>
+  static constexpr nsCycleCollectionParticipant*
+  GetHelper(double)
+  {
+    return nullptr;
+  }
+
+public:
+  static constexpr nsCycleCollectionParticipant*
+  Get()
+  {
+    // Passing int() here will try to call the GetHelper that takes an int as
+    // its firt argument. If T doesn't participate in CC then substitution for
+    // the second argument (with a default value) will fail and because of
+    // SFINAE the next best match (the variant taking a double) will be called.
+    return GetHelper<T>(int());
+  }
+};
+
+template<class T>
+class GetCCParticipant<T, true>
+{
+public:
+  static constexpr nsCycleCollectionParticipant*
+  Get()
+  {
+    return nullptr;
+  }
+};
+
+void
+FinalizeGlobal(JSFreeOp* aFop, JSObject* aObj);
+
+bool
+ResolveGlobal(JSContext* aCx, JS::Handle<JSObject*> aObj,
+              JS::Handle<jsid> aId, bool* aResolvedp);
+
+bool
+MayResolveGlobal(const JSAtomState& aNames, jsid aId, JSObject* aMaybeObj);
+
+bool
+EnumerateGlobal(JSContext* aCx, JS::Handle<JSObject*> aObj);
+
+template <class T>
+struct CreateGlobalOptions
+{
+  static constexpr ProtoAndIfaceCache::Kind ProtoAndIfaceCacheKind =
+    ProtoAndIfaceCache::NonWindowLike;
+  static void TraceGlobal(JSTracer* aTrc, JSObject* aObj)
+  {
+    mozilla::dom::TraceProtoAndIfaceCache(aTrc, aObj);
+  }
+  static bool PostCreateGlobal(JSContext* aCx, JS::Handle<JSObject*> aGlobal)
+  {
+    MOZ_ALWAYS_TRUE(TryPreserveWrapper(aGlobal));
+
+    return true;
+  }
+};
+
+template <>
+struct CreateGlobalOptions<nsGlobalWindow>
+{
+  static constexpr ProtoAndIfaceCache::Kind ProtoAndIfaceCacheKind =
+    ProtoAndIfaceCache::WindowLike;
+  static void TraceGlobal(JSTracer* aTrc, JSObject* aObj);
+  static bool PostCreateGlobal(JSContext* aCx, JS::Handle<JSObject*> aGlobal);
+};
+
+nsresult
+RegisterDOMNames();
+
+// The return value is true if we created and successfully performed our part of
+// the setup for the global, false otherwise.
+//
+// Typically this method's caller will want to ensure that
+// xpc::InitGlobalObjectOptions is called before, and xpc::InitGlobalObject is
+// called after, this method, to ensure that this global object and its
+// compartment are consistent with other global objects.
+template <class T, ProtoHandleGetter GetProto>
+bool
+CreateGlobal(JSContext* aCx, T* aNative, nsWrapperCache* aCache,
+             const JSClass* aClass, JS::CompartmentOptions& aOptions,
+             JSPrincipals* aPrincipal, bool aInitStandardClasses,
+             JS::MutableHandle<JSObject*> aGlobal)
+{
+  aOptions.creationOptions().setTrace(CreateGlobalOptions<T>::TraceGlobal);
+  if (xpc::SharedMemoryEnabled()) {
+    aOptions.creationOptions().setSharedMemoryAndAtomicsEnabled(true);
+  }
+
+  aGlobal.set(JS_NewGlobalObject(aCx, aClass, aPrincipal,
+                                 JS::DontFireOnNewGlobalHook, aOptions));
+  if (!aGlobal) {
+    NS_WARNING("Failed to create global");
+    return false;
+  }
+
+  JSAutoCompartment ac(aCx, aGlobal);
+
+  {
+    js::SetReservedSlot(aGlobal, DOM_OBJECT_SLOT, JS::PrivateValue(aNative));
+    NS_ADDREF(aNative);
+
+    aCache->SetWrapper(aGlobal);
+
+    dom::AllocateProtoAndIfaceCache(aGlobal,
+                                    CreateGlobalOptions<T>::ProtoAndIfaceCacheKind);
+
+    if (!CreateGlobalOptions<T>::PostCreateGlobal(aCx, aGlobal)) {
+      return false;
+    }
+  }
+
+  if (aInitStandardClasses &&
+      !JS_InitStandardClasses(aCx, aGlobal)) {
+    NS_WARNING("Failed to init standard classes");
+    return false;
+  }
+
+  JS::Handle<JSObject*> proto = GetProto(aCx);
+  if (!proto || !JS_SplicePrototype(aCx, aGlobal, proto)) {
+    NS_WARNING("Failed to set proto");
+    return false;
+  }
+
+  bool succeeded;
+  if (!JS_SetImmutablePrototype(aCx, aGlobal, &succeeded)) {
+    return false;
+  }
+  MOZ_ASSERT(succeeded,
+             "making a fresh global object's [[Prototype]] immutable can "
+             "internally fail, but it should never be unsuccessful");
+
+  return true;
+}
+
+/*
+ * Holds a jsid that is initialized to a pinned string, with automatic
+ * conversion to Handle<jsid>, as it is held live forever by pinning.
+ */
+class PinnedStringId
+{
+  jsid id;
+
+ public:
+  PinnedStringId() : id(JSID_VOID) {}
+
+  bool init(JSContext *cx, const char *string) {
+    JSString* str = JS_AtomizeAndPinString(cx, string);
+    if (!str)
+      return false;
+    id = INTERNED_STRING_TO_JSID(cx, str);
+    return true;
+  }
+
+  operator const jsid& () {
+    return id;
+  }
+
+  operator JS::Handle<jsid> () {
+    /* This is safe because we have pinned the string. */
+    return JS::Handle<jsid>::fromMarkedLocation(&id);
+  }
+};
+
+bool
+GenericBindingGetter(JSContext* cx, unsigned argc, JS::Value* vp);
+
+bool
+GenericBindingSetter(JSContext* cx, unsigned argc, JS::Value* vp);
+
+bool
+GenericBindingMethod(JSContext* cx, unsigned argc, JS::Value* vp);
+
+bool
+GenericPromiseReturningBindingMethod(JSContext* cx, unsigned argc, JS::Value* vp);
+
+bool
+StaticMethodPromiseWrapper(JSContext* cx, unsigned argc, JS::Value* vp);
+
+// ConvertExceptionToPromise should only be called when we have an error
+// condition (e.g. returned false from a JSAPI method).  Note that there may be
+// no exception on cx, in which case this is an uncatchable failure that will
+// simply be propagated.  Otherwise this method will attempt to convert the
+// exception to a Promise rejected with the exception that it will store in
+// rval.
+//
+// promiseScope should be the scope in which the Promise should be created.
+bool
+ConvertExceptionToPromise(JSContext* cx,
+                          JSObject* promiseScope,
+                          JS::MutableHandle<JS::Value> rval);
+
+#ifdef DEBUG
+void
+AssertReturnTypeMatchesJitinfo(const JSJitInfo* aJitinfo,
+                               JS::Handle<JS::Value> aValue);
+#endif
+
+// This function is called by the bindings layer for methods/getters/setters
+// that are not safe to be called in prerendering mode.  It checks to make sure
+// that the |this| object is not running in a global that is in prerendering
+// mode.  Otherwise, it aborts execution of timers and event handlers, and
+// returns false which gets converted to an uncatchable exception by the
+// bindings layer.
+bool
+EnforceNotInPrerendering(JSContext* aCx, JSObject* aObj);
+
+// Handles the violation of a blacklisted action in prerendering mode by
+// aborting the scripts, and preventing timers and event handlers from running
+// in the window in the future.
+void
+HandlePrerenderingViolation(nsPIDOMWindowInner* aWindow);
+
+bool
+CallerSubsumes(JSObject* aObject);
+
+MOZ_ALWAYS_INLINE bool
+CallerSubsumes(JS::Handle<JS::Value> aValue)
+{
+  if (!aValue.isObject()) {
+    return true;
+  }
+  return CallerSubsumes(&aValue.toObject());
+}
+
+template<class T>
+inline bool
+WrappedJSToDictionary(JSContext* aCx, nsISupports* aObject, T& aDictionary)
+{
+  nsCOMPtr<nsIXPConnectWrappedJS> wrappedObj = do_QueryInterface(aObject);
+  if (!wrappedObj) {
+    return false;
+  }
+
+  JS::Rooted<JSObject*> obj(aCx, wrappedObj->GetJSObject());
+  if (!obj) {
+    return false;
+  }
+
+  JSAutoCompartment ac(aCx, obj);
+  JS::Rooted<JS::Value> v(aCx, JS::ObjectValue(*obj));
+  return aDictionary.Init(aCx, v);
+}
+
+template<class T>
+inline bool
+WrappedJSToDictionary(nsISupports* aObject, T& aDictionary)
+{
+  nsCOMPtr<nsIXPConnectWrappedJS> wrappedObj = do_QueryInterface(aObject);
+  NS_ENSURE_TRUE(wrappedObj, false);
+  JS::Rooted<JSObject*> obj(RootingCx(), wrappedObj->GetJSObject());
+  NS_ENSURE_TRUE(obj, false);
+
+  nsIGlobalObject* global = xpc::NativeGlobal(obj);
+  NS_ENSURE_TRUE(global, false);
+
+  // we need this AutoEntryScript here because the spec requires us to execute
+  // getters when parsing a dictionary
+  AutoEntryScript aes(global, "WebIDL dictionary creation");
+
+  JS::Rooted<JS::Value> v(aes.cx(), JS::ObjectValue(*obj));
+  return aDictionary.Init(aes.cx(), v);
+}
+
+
+template<class T, class S>
+inline RefPtr<T>
+StrongOrRawPtr(already_AddRefed<S>&& aPtr)
+{
+  return aPtr.template downcast<T>();
+}
+
+template<class T,
+         class ReturnType=typename Conditional<IsRefcounted<T>::value, T*,
+                                               nsAutoPtr<T>>::Type>
+inline ReturnType
+StrongOrRawPtr(T* aPtr)
+{
+  return ReturnType(aPtr);
+}
+
+template<class T, template<typename> class SmartPtr, class S>
+inline void
+StrongOrRawPtr(SmartPtr<S>&& aPtr) = delete;
+
+template<class T>
+struct StrongPtrForMember
+{
+  typedef typename Conditional<IsRefcounted<T>::value,
+                               RefPtr<T>, nsAutoPtr<T>>::Type Type;
+};
+
+namespace binding_detail {
+inline
+JSObject*
+GetHackedNamespaceProtoObject(JSContext* aCx)
+{
+  return JS_NewPlainObject(aCx);
+}
+} // namespace binding_detail
+
+// Resolve an id on the given global object that wants to be included in
+// Exposed=System webidl annotations.  False return value means exception
+// thrown.
+bool SystemGlobalResolve(JSContext* cx, JS::Handle<JSObject*> obj,
+                         JS::Handle<jsid> id, bool* resolvedp);
+
+// Enumerate all ids on the given global object that wants to be included in
+// Exposed=System webidl annotations.  False return value means exception
+// thrown.
+bool SystemGlobalEnumerate(JSContext* cx, JS::Handle<JSObject*> obj);
+
+// Slot indexes for maplike/setlike forEach functions
+#define FOREACH_CALLBACK_SLOT 0
+#define FOREACH_MAPLIKEORSETLIKEOBJ_SLOT 1
+
+// Backing function for running .forEach() on maplike/setlike interfaces.
+// Unpacks callback and maplike/setlike object from reserved slots, then runs
+// callback for each key (and value, for maplikes)
+bool ForEachHandler(JSContext* aCx, unsigned aArgc, JS::Value* aVp);
+
+// Unpacks backing object (ES6 map/set) from the reserved slot of a reflector
+// for a maplike/setlike interface. If backing object does not exist, creates
+// backing object in the compartment of the reflector involved, making this safe
+// to use across compartments/via xrays. Return values of these methods will
+// always be in the context compartment.
+bool GetMaplikeBackingObject(JSContext* aCx, JS::Handle<JSObject*> aObj,
+                             size_t aSlotIndex,
+                             JS::MutableHandle<JSObject*> aBackingObj,
+                             bool* aBackingObjCreated);
+bool GetSetlikeBackingObject(JSContext* aCx, JS::Handle<JSObject*> aObj,
+                             size_t aSlotIndex,
+                             JS::MutableHandle<JSObject*> aBackingObj,
+                             bool* aBackingObjCreated);
+
+// Get the desired prototype object for an object construction from the given
+// CallArgs.  Null is returned if the default prototype should be used.
+bool
+GetDesiredProto(JSContext* aCx, const JS::CallArgs& aCallArgs,
+                JS::MutableHandle<JSObject*> aDesiredProto);
+
+void
+SetDocumentAndPageUseCounter(JSContext* aCx, JSObject* aObject,
+                             UseCounter aUseCounter);
+
+// Warnings
+void
+DeprecationWarning(JSContext* aCx, JSObject* aObject,
+                   nsIDocument::DeprecatedOperations aOperation);
+
+// A callback to perform funToString on an interface object
+JSString*
+InterfaceObjectToString(JSContext* aCx, JS::Handle<JSObject*> aObject,
+                        unsigned /* indent */);
+
+namespace binding_detail {
+// Get a JS global object that can be used for some temporary allocations.  The
+// idea is that this should be used for situations when you need to operate in
+// _some_ compartment but don't care which one.  A typical example is when you
+// have non-JS input, non-JS output, but have to go through some sort of JS
+// representation in the middle, so need a compartment to allocate things in.
+//
+// It's VERY important that any consumers of this function only do things that
+// are guaranteed to be side-effect-free, even in the face of a script
+// environment controlled by a hostile adversary.  This is because in the worker
+// case the global is in fact the worker global, so it and its standard objects
+// are controlled by the worker script.  This is why this function is in the
+// binding_detail namespace.  Any use of this function MUST be very carefully
+// reviewed by someone who is sufficiently devious and has a very good
+// understanding of all the code that will run while we're using the return
+// value, including the SpiderMonkey parts.
+JSObject* UnprivilegedJunkScopeOrWorkerGlobal();
+} // namespace binding_detail
+
+} // namespace dom
+} // namespace mozilla
+
+#endif /* mozilla_dom_BindingUtils_h__ */