Merge branch 'master' into js-modules

# Conflicts:
#	modules/libpref/init/all.js

25 files changed, 78 insertions, 789 deletions

diff --git a/dom/html/HTMLCanvasElement.cpp b/dom/html/HTMLCanvasElement.cpp
index 88b41bce0..4b5deab18 100644
--- a/dom/html/HTMLCanvasElement.cpp
+++ b/dom/html/HTMLCanvasElement.cpp
@@ -42,7 +42,6 @@
 #include "nsRefreshDriver.h"
 #include "nsStreamUtils.h"
 #include "ActiveLayerTracker.h"
-#include "VRManagerChild.h"
 #include "WebGL1Context.h"
 #include "WebGL2Context.h"
 
@@ -358,7 +357,6 @@ NS_IMPL_ISUPPORTS(HTMLCanvasElementObserver, nsIObserver)
 HTMLCanvasElement::HTMLCanvasElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
   : nsGenericHTMLElement(aNodeInfo),
     mResetLayer(true) ,
-    mVRPresentationActive(false),
     mWriteOnly(false)
 {}
 
@@ -554,17 +552,23 @@ HTMLCanvasElement::CopyInnerTo(Element* aDest)
     HTMLCanvasElement* dest = static_cast<HTMLCanvasElement*>(aDest);
     dest->mOriginalCanvas = this;
 
-    nsCOMPtr<nsISupports> cxt;
-    dest->GetContext(NS_LITERAL_STRING("2d"), getter_AddRefs(cxt));
-    RefPtr<CanvasRenderingContext2D> context2d =
-      static_cast<CanvasRenderingContext2D*>(cxt.get());
-    if (context2d && !mPrintCallback) {
-      CanvasImageSource source;
-      source.SetAsHTMLCanvasElement() = this;
-      ErrorResult err;
-      context2d->DrawImage(source,
-                           0.0, 0.0, err);
-      rv = err.StealNSResult();
+    // We make sure that the canvas is not zero sized since that would cause
+    // the DrawImage call below to return an error, which would cause printing
+    // to fail.
+    nsIntSize size = GetWidthHeight();
+    if (size.height > 0 && size.width > 0) {
+      nsCOMPtr<nsISupports> cxt;
+      dest->GetContext(NS_LITERAL_STRING("2d"), getter_AddRefs(cxt));
+      RefPtr<CanvasRenderingContext2D> context2d =
+        static_cast<CanvasRenderingContext2D*>(cxt.get());
+      if (context2d && !mPrintCallback) {
+        CanvasImageSource source;
+        source.SetAsHTMLCanvasElement() = this;
+        ErrorResult err;
+        context2d->DrawImage(source,
+                             0.0, 0.0, err);
+        rv = err.StealNSResult();
+      }
     }
   }
   return rv;
@@ -1002,7 +1006,7 @@ HTMLCanvasElement::GetSize()
 }
 
 bool
-HTMLCanvasElement::IsWriteOnly()
+HTMLCanvasElement::IsWriteOnly() const
 {
   return mWriteOnly;
 }
@@ -1111,7 +1115,7 @@ HTMLCanvasElement::GetCanvasLayer(nsDisplayListBuilder* aBuilder,
   static uint8_t sOffscreenCanvasLayerUserDataDummy = 0;
 
   if (mCurrentContext) {
-    return mCurrentContext->GetCanvasLayer(aBuilder, aOldLayer, aManager, mVRPresentationActive);
+    return mCurrentContext->GetCanvasLayer(aBuilder, aOldLayer, aManager);
   }
 
   if (mOffscreenCanvas) {
@@ -1441,42 +1445,5 @@ HTMLCanvasElement::InvalidateFromAsyncCanvasRenderer(AsyncCanvasRenderer *aRende
   element->InvalidateCanvasContent(nullptr);
 }
 
-void
-HTMLCanvasElement::StartVRPresentation()
-{
-  WebGLContext* webgl = static_cast<WebGLContext*>(GetContextAtIndex(0));
-  if (!webgl) {
-    return;
-  }
-
-  if (!webgl->StartVRPresentation()) {
-    return;
-  }
-
-  mVRPresentationActive = true;
-}
-
-void
-HTMLCanvasElement::StopVRPresentation()
-{
-  mVRPresentationActive = false;
-}
-
-already_AddRefed<layers::SharedSurfaceTextureClient>
-HTMLCanvasElement::GetVRFrame()
-{
-  if (GetCurrentContextType() != CanvasContextType::WebGL1 &&
-      GetCurrentContextType() != CanvasContextType::WebGL2) {
-    return nullptr;
-  }
-
-  WebGLContext* webgl = static_cast<WebGLContext*>(GetContextAtIndex(0));
-  if (!webgl) {
-    return nullptr;
-  }
-
-  return webgl->GetVRFrame();
-}
-
 } // namespace dom
 } // namespace mozilla
diff --git a/dom/html/HTMLCanvasElement.h b/dom/html/HTMLCanvasElement.h
index 81c141d3c..e77db6ff1 100644
--- a/dom/html/HTMLCanvasElement.h
+++ b/dom/html/HTMLCanvasElement.h
@@ -224,9 +224,9 @@ public:
   nsIntSize GetSize();
 
   /**
-   * Determine whether the canvas is write-only.
+   * Determine whether the canvas is write-only (tainted).
    */
-  bool IsWriteOnly();
+  bool IsWriteOnly() const;
 
   /**
    * Force the canvas to be write-only.
@@ -350,10 +350,6 @@ public:
   static void SetAttrFromAsyncCanvasRenderer(AsyncCanvasRenderer *aRenderer);
   static void InvalidateFromAsyncCanvasRenderer(AsyncCanvasRenderer *aRenderer);
 
-  void StartVRPresentation();
-  void StopVRPresentation();
-  already_AddRefed<layers::SharedSurfaceTextureClient> GetVRFrame();
-
 protected:
   virtual ~HTMLCanvasElement();
 
diff --git a/dom/html/HTMLFormControlsCollection.cpp b/dom/html/HTMLFormControlsCollection.cpp
index d91a6b5de..77fafae99 100644
--- a/dom/html/HTMLFormControlsCollection.cpp
+++ b/dom/html/HTMLFormControlsCollection.cpp
@@ -134,7 +134,6 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(HTMLFormControlsCollection)
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(HTMLFormControlsCollection)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mNameLookupTable)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN(HTMLFormControlsCollection)
   NS_IMPL_CYCLE_COLLECTION_TRACE_PRESERVED_WRAPPER
diff --git a/dom/html/HTMLFormElement.cpp b/dom/html/HTMLFormElement.cpp
index 5164391f8..6bea19a2b 100644
--- a/dom/html/HTMLFormElement.cpp
+++ b/dom/html/HTMLFormElement.cpp
@@ -38,7 +38,6 @@
 // form submission
 #include "HTMLFormSubmissionConstants.h"
 #include "mozilla/dom/FormData.h"
-#include "mozilla/Telemetry.h"
 #include "nsIFormSubmitObserver.h"
 #include "nsIObserverService.h"
 #include "nsICategoryManager.h"
@@ -52,7 +51,6 @@
 #include "nsIWebProgress.h"
 #include "nsIDocShell.h"
 #include "nsIPrompt.h"
-#include "nsISecurityUITelemetry.h"
 #include "nsIStringBundle.h"
 
 // radio buttons
@@ -955,15 +953,6 @@ HTMLFormElement::DoSecureToInsecureSubmitCheck(nsIURI* aActionURL,
     return rv;
   }
   *aCancelSubmit = (buttonPressed == 1);
-  uint32_t telemetryBucket =
-    nsISecurityUITelemetry::WARNING_CONFIRM_POST_TO_INSECURE_FROM_SECURE;
-  mozilla::Telemetry::Accumulate(mozilla::Telemetry::SECURITY_UI,
-                                 telemetryBucket);
-  if (!*aCancelSubmit) {
-    // The user opted to continue, so note that in the next telemetry bucket.
-    mozilla::Telemetry::Accumulate(mozilla::Telemetry::SECURITY_UI,
-                                   telemetryBucket + 1);
-  }
   return NS_OK;
 }
 
diff --git a/dom/html/HTMLImageElement.cpp b/dom/html/HTMLImageElement.cpp
index 4b2e7a07b..fab1cdef4 100644
--- a/dom/html/HTMLImageElement.cpp
+++ b/dom/html/HTMLImageElement.cpp
@@ -1345,8 +1345,6 @@ HTMLImageElement::FlushUseCounters()
 
   nsCOMPtr<imgIContainer> container;
   request->GetImage(getter_AddRefs(container));
-
-  static_cast<image::Image*>(container.get())->ReportUseCounters();
 }
 
 } // namespace dom
diff --git a/dom/html/HTMLInputElement.cpp b/dom/html/HTMLInputElement.cpp
index e9086933b..0b879bb9b 100644
--- a/dom/html/HTMLInputElement.cpp
+++ b/dom/html/HTMLInputElement.cpp
@@ -24,7 +24,6 @@
 #include "nsIPhonetic.h"
 
 #include "HTMLFormSubmissionConstants.h"
-#include "mozilla/Telemetry.h"
 #include "nsIControllers.h"
 #include "nsIStringBundle.h"
 #include "nsFocusManager.h"
@@ -1275,10 +1274,6 @@ HTMLInputElement::BeforeSetAttr(int32_t aNameSpaceID, nsIAtom* aName,
         container->RadioRequiredWillChange(name, !!aValue);
       }
     }
-
-    if (aName == nsGkAtoms::webkitdirectory) {
-      Telemetry::Accumulate(Telemetry::WEBKIT_DIRECTORY_USED, true);
-    }
   }
 
   return nsGenericHTMLFormElementWithState::BeforeSetAttr(aNameSpaceID, aName,
@@ -4989,10 +4984,6 @@ HTMLInputElement::BindToTree(nsIDocument* aDocument, nsIContent* aParent,
                                  true);
       dispatcher->PostDOMEvent();
     }
-
-#ifdef EARLY_BETA_OR_EARLIER
-    Telemetry::Accumulate(Telemetry::PWMGR_PASSWORD_INPUT_IN_FORM, !!mForm);
-#endif
   }
 
   return rv;
@@ -8863,7 +8854,6 @@ HTMLInputElement::UpdateEntries(const nsTArray<OwningFileOrDirectory>& aFilesOrD
 void
 HTMLInputElement::GetWebkitEntries(nsTArray<RefPtr<FileSystemEntry>>& aSequence)
 {
-  Telemetry::Accumulate(Telemetry::BLINK_FILESYSTEM_USED, true);
   aSequence.AppendElements(mEntries);
 }
 
diff --git a/dom/html/HTMLMediaElement.cpp b/dom/html/HTMLMediaElement.cpp
index 3954e6208..050d1ac69 100644
--- a/dom/html/HTMLMediaElement.cpp
+++ b/dom/html/HTMLMediaElement.cpp
@@ -92,7 +92,6 @@
 #include "mozilla/dom/VideoTrackList.h"
 #include "mozilla/dom/TextTrack.h"
 #include "nsIContentPolicy.h"
-#include "mozilla/Telemetry.h"
 #include "DecoderDoctorDiagnostics.h"
 #include "DecoderTraits.h"
 #include "MediaContentType.h"
@@ -1038,14 +1037,6 @@ void HTMLMediaElement::ShutdownDecoder()
 
 void HTMLMediaElement::AbortExistingLoads()
 {
-#ifdef MOZ_EME
-  // If there is no existing decoder then we don't have anything to
-  // report. This prevents reporting the initial load from an
-  // empty video element as a failed EME load.
-  if (mDecoder) {
-    ReportEMETelemetry();
-  }
-#endif
   // Abort any already-running instance of the resource selection algorithm.
   mLoadWaitStatus = NOT_WAITING;
 
@@ -1901,8 +1892,6 @@ NS_IMETHODIMP HTMLMediaElement::GetCurrentTime(double* aCurrentTime)
 void
 HTMLMediaElement::FastSeek(double aTime, ErrorResult& aRv)
 {
-  LOG(LogLevel::Debug, ("Reporting telemetry VIDEO_FASTSEEK_USED"));
-  Telemetry::Accumulate(Telemetry::VIDEO_FASTSEEK_USED, 1);
   RefPtr<Promise> tobeDropped = Seek(aTime, SeekTarget::PrevSyncPoint, aRv);
 }
 
@@ -3156,10 +3145,6 @@ HTMLMediaElement::~HTMLMediaElement()
   if (mProgressTimer) {
     StopProgress();
   }
-  if (mVideoDecodeSuspendTimer) {
-    mVideoDecodeSuspendTimer->Cancel();
-    mVideoDecodeSuspendTimer = nullptr;
-  }
   if (mSrcStream) {
     EndSrcMediaStreamPlayback();
   }
@@ -3650,228 +3635,6 @@ nsresult HTMLMediaElement::BindToTree(nsIDocument* aDocument, nsIContent* aParen
   return rv;
 }
 
-/* static */
-void HTMLMediaElement::VideoDecodeSuspendTimerCallback(nsITimer* aTimer, void* aClosure)
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  auto element = static_cast<HTMLMediaElement*>(aClosure);
-  element->mVideoDecodeSuspendTime.Start();
-  element->mVideoDecodeSuspendTimer = nullptr;
-}
-
-void HTMLMediaElement::HiddenVideoStart()
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  mHiddenPlayTime.Start();
-  if (mVideoDecodeSuspendTimer) {
-    // Already started, just keep it running.
-    return;
-  }
-  mVideoDecodeSuspendTimer = do_CreateInstance("@mozilla.org/timer;1");
-  mVideoDecodeSuspendTimer->InitWithNamedFuncCallback(
-    VideoDecodeSuspendTimerCallback, this,
-    MediaPrefs::MDSMSuspendBackgroundVideoDelay(), nsITimer::TYPE_ONE_SHOT,
-    "HTMLMediaElement::VideoDecodeSuspendTimerCallback");
-}
-
-void HTMLMediaElement::HiddenVideoStop()
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  mHiddenPlayTime.Pause();
-  mVideoDecodeSuspendTime.Pause();
-  if (!mVideoDecodeSuspendTimer) {
-    return;
-  }
-  mVideoDecodeSuspendTimer->Cancel();
-  mVideoDecodeSuspendTimer = nullptr;
-}
-
-#ifdef MOZ_EME
-void
-HTMLMediaElement::ReportEMETelemetry()
-{
-  // Report telemetry for EME videos when a page is unloaded.
-  NS_ASSERTION(NS_IsMainThread(), "Should be on main thread.");
-  if (mIsEncrypted && Preferences::GetBool("media.eme.enabled")) {
-    Telemetry::Accumulate(Telemetry::VIDEO_EME_PLAY_SUCCESS, mLoadedDataFired);
-    LOG(LogLevel::Debug, ("%p VIDEO_EME_PLAY_SUCCESS = %s",
-                       this, mLoadedDataFired ? "true" : "false"));
-  }
-}
-#endif
-
-void
-HTMLMediaElement::ReportTelemetry()
-{
-  // Report telemetry for videos when a page is unloaded. We
-  // want to know data on what state the video is at when
-  // the user has exited.
-  enum UnloadedState {
-    ENDED = 0,
-    PAUSED = 1,
-    STALLED = 2,
-    SEEKING = 3,
-    OTHER = 4
-  };
-
-  UnloadedState state = OTHER;
-  if (Seeking()) {
-    state = SEEKING;
-  }
-  else if (Ended()) {
-    state = ENDED;
-  }
-  else if (Paused()) {
-    state = PAUSED;
-  }
-  else {
-    // For buffering we check if the current playback position is at the end
-    // of a buffered range, within a margin of error. We also consider to be
-    // buffering if the last frame status was buffering and the ready state is
-    // HAVE_CURRENT_DATA to account for times where we are in a buffering state
-    // regardless of what actual data we have buffered.
-    bool stalled = false;
-    RefPtr<TimeRanges> ranges = Buffered();
-    const double errorMargin = 0.05;
-    double t = CurrentTime();
-    TimeRanges::index_type index = ranges->Find(t, errorMargin);
-    ErrorResult ignore;
-    stalled = index != TimeRanges::NoIndex &&
-              (ranges->End(index, ignore) - t) < errorMargin;
-    stalled |= mDecoder && NextFrameStatus() == MediaDecoderOwner::NEXT_FRAME_UNAVAILABLE_BUFFERING &&
-               mReadyState == HTMLMediaElement::HAVE_CURRENT_DATA;
-    if (stalled) {
-      state = STALLED;
-    }
-  }
-
-  Telemetry::Accumulate(Telemetry::VIDEO_UNLOAD_STATE, state);
-  LOG(LogLevel::Debug, ("%p VIDEO_UNLOAD_STATE = %d", this, state));
-
-  FrameStatisticsData data;
-
-  if (HTMLVideoElement* vid = HTMLVideoElement::FromContentOrNull(this)) {
-    FrameStatistics* stats = vid->GetFrameStatistics();
-    if (stats) {
-      data = stats->GetFrameStatisticsData();
-      if (data.mParsedFrames) {
-        MOZ_ASSERT(data.mDroppedFrames <= data.mParsedFrames);
-        // Dropped frames <= total frames, so 'percentage' cannot be higher than
-        // 100 and therefore can fit in a uint32_t (that Telemetry takes).
-        uint32_t percentage = 100 * data.mDroppedFrames / data.mParsedFrames;
-        LOG(LogLevel::Debug,
-            ("Reporting telemetry DROPPED_FRAMES_IN_VIDEO_PLAYBACK"));
-        Telemetry::Accumulate(Telemetry::VIDEO_DROPPED_FRAMES_PROPORTION,
-                              percentage);
-      }
-    }
-  }
-
-  if (mMediaInfo.HasVideo() &&
-      mMediaInfo.mVideo.mImage.height > 0) {
-    // We have a valid video.
-    double playTime = mPlayTime.Total();
-    double hiddenPlayTime = mHiddenPlayTime.Total();
-    double videoDecodeSuspendTime = mVideoDecodeSuspendTime.Total();
-
-    Telemetry::Accumulate(Telemetry::VIDEO_PLAY_TIME_MS, SECONDS_TO_MS(playTime));
-    LOG(LogLevel::Debug, ("%p VIDEO_PLAY_TIME_MS = %f", this, playTime));
-
-    Telemetry::Accumulate(Telemetry::VIDEO_HIDDEN_PLAY_TIME_MS, SECONDS_TO_MS(hiddenPlayTime));
-    LOG(LogLevel::Debug, ("%p VIDEO_HIDDEN_PLAY_TIME_MS = %f", this, hiddenPlayTime));
-
-    if (playTime > 0.0) {
-      // We have actually played something -> Report some valid-video telemetry.
-
-      // Keyed by audio+video or video alone, and by a resolution range.
-      nsCString key(mMediaInfo.HasAudio() ? "AV," : "V,");
-      static const struct { int32_t mH; const char* mRes; } sResolutions[] = {
-        {  240, "0<h<=240" },
-        {  480, "240<h<=480" },
-        {  576, "480<h<=576" },
-        {  720, "576<h<=720" },
-        { 1080, "720<h<=1080" },
-        { 2160, "1080<h<=2160" }
-      };
-      const char* resolution = "h>2160";
-      int32_t height = mMediaInfo.mVideo.mImage.height;
-      for (const auto& res : sResolutions) {
-        if (height <= res.mH) {
-          resolution = res.mRes;
-          break;
-        }
-      }
-      key.AppendASCII(resolution);
-
-      uint32_t hiddenPercentage = uint32_t(hiddenPlayTime / playTime * 100.0 + 0.5);
-      Telemetry::Accumulate(Telemetry::VIDEO_HIDDEN_PLAY_TIME_PERCENTAGE,
-                            key,
-                            hiddenPercentage);
-      // Also accumulate all percentages in an "All" key.
-      Telemetry::Accumulate(Telemetry::VIDEO_HIDDEN_PLAY_TIME_PERCENTAGE,
-                            NS_LITERAL_CSTRING("All"),
-                            hiddenPercentage);
-      LOG(LogLevel::Debug, ("%p VIDEO_HIDDEN_PLAY_TIME_PERCENTAGE = %u, keys: '%s' and 'All'",
-                            this, hiddenPercentage, key.get()));
-
-      uint32_t videoDecodeSuspendPercentage =
-        uint32_t(videoDecodeSuspendTime / playTime * 100.0 + 0.5);
-      Telemetry::Accumulate(Telemetry::VIDEO_INFERRED_DECODE_SUSPEND_PERCENTAGE,
-                            key,
-                            videoDecodeSuspendPercentage);
-      Telemetry::Accumulate(Telemetry::VIDEO_INFERRED_DECODE_SUSPEND_PERCENTAGE,
-                            NS_LITERAL_CSTRING("All"),
-                            videoDecodeSuspendPercentage);
-      LOG(LogLevel::Debug, ("%p VIDEO_INFERRED_DECODE_SUSPEND_PERCENTAGE = %u, keys: '%s' and 'All'",
-                            this, videoDecodeSuspendPercentage, key.get()));
-
-      if (data.mInterKeyframeCount != 0) {
-        uint32_t average_ms =
-          uint32_t(std::min<uint64_t>(double(data.mInterKeyframeSum_us)
-                                      / double(data.mInterKeyframeCount)
-                                      / 1000.0
-                                      + 0.5,
-                                      UINT32_MAX));
-        Telemetry::Accumulate(Telemetry::VIDEO_INTER_KEYFRAME_AVERAGE_MS,
-                              key,
-                              average_ms);
-        Telemetry::Accumulate(Telemetry::VIDEO_INTER_KEYFRAME_AVERAGE_MS,
-                              NS_LITERAL_CSTRING("All"),
-                              average_ms);
-        LOG(LogLevel::Debug, ("%p VIDEO_INTER_KEYFRAME_AVERAGE_MS = %u, keys: '%s' and 'All'",
-                              this, average_ms, key.get()));
-
-        uint32_t max_ms =
-          uint32_t(std::min<uint64_t>((data.mInterKeyFrameMax_us + 500) / 1000,
-                                      UINT32_MAX));
-        Telemetry::Accumulate(Telemetry::VIDEO_INTER_KEYFRAME_MAX_MS,
-                              key,
-                              max_ms);
-        Telemetry::Accumulate(Telemetry::VIDEO_INTER_KEYFRAME_MAX_MS,
-                              NS_LITERAL_CSTRING("All"),
-                              max_ms);
-        LOG(LogLevel::Debug, ("%p VIDEO_INTER_KEYFRAME_MAX_MS = %u, keys: '%s' and 'All'",
-                              this, max_ms, key.get()));
-      } else {
-        // Here, we have played *some* of the video, but didn't get more than 1
-        // keyframe. Report '0' if we have played for longer than the video-
-        // decode-suspend delay (showing recovery would be difficult).
-        uint32_t suspendDelay_ms = MediaPrefs::MDSMSuspendBackgroundVideoDelay();
-        if (uint32_t(playTime * 1000.0) > suspendDelay_ms) {
-          Telemetry::Accumulate(Telemetry::VIDEO_INTER_KEYFRAME_MAX_MS,
-                                key,
-                                0);
-          Telemetry::Accumulate(Telemetry::VIDEO_INTER_KEYFRAME_MAX_MS,
-                                NS_LITERAL_CSTRING("All"),
-                                0);
-          LOG(LogLevel::Debug, ("%p VIDEO_INTER_KEYFRAME_MAX_MS = 0 (only 1 keyframe), keys: '%s' and 'All'",
-                                this, key.get()));
-        }
-      }
-    }
-  }
-}
-
 void HTMLMediaElement::UnbindFromTree(bool aDeep,
                                       bool aNullParent)
 {
@@ -5351,19 +5114,6 @@ nsresult HTMLMediaElement::DispatchAsyncEvent(const nsAString& aName)
   nsCOMPtr<nsIRunnable> event = new nsAsyncEventRunner(aName, this);
   NS_DispatchToMainThread(event);
 
-  if ((aName.EqualsLiteral("play") || aName.EqualsLiteral("playing"))) {
-    mPlayTime.Start();
-    if (IsHidden()) {
-      HiddenVideoStart();
-    }
-  } else if (aName.EqualsLiteral("waiting")) {
-    mPlayTime.Pause();
-    HiddenVideoStop();
-  } else if (aName.EqualsLiteral("pause")) {
-    mPlayTime.Pause();
-    HiddenVideoStop();
-  }
-
   return NS_OK;
 }
 
@@ -5489,11 +5239,6 @@ void HTMLMediaElement::SuspendOrResumeElement(bool aPauseElement, bool aSuspendE
     UpdateSrcMediaStreamPlaying();
     UpdateAudioChannelPlayingState();
     if (aPauseElement) {
-      ReportTelemetry();
-#ifdef MOZ_EME
-      ReportEMETelemetry();
-#endif
-
 #ifdef MOZ_EME
       // For EME content, we may force destruction of the CDM client (and CDM
       // instance if this is the last client for that CDM instance) and
@@ -5545,13 +5290,6 @@ bool HTMLMediaElement::IsBeingDestroyed()
 void HTMLMediaElement::NotifyOwnerDocumentActivityChanged()
 {
   bool visible = !IsHidden();
-  if (visible) {
-    // Visible -> Just pause hidden play time (no-op if already paused).
-    HiddenVideoStop();
-  } else if (mPlayTime.IsStarted()) {
-    // Not visible, play time is running -> Start hidden play time if needed.
-    HiddenVideoStart();
-  }
 
   if (mDecoder && !IsBeingDestroyed()) {
     mDecoder->NotifyOwnerActivityChanged(visible);
@@ -6327,18 +6065,10 @@ HTMLMediaElement::OnVisibilityChange(Visibility aNewVisibility)
         break;
     }
     case Visibility::APPROXIMATELY_NONVISIBLE: {
-      if (mPlayTime.IsStarted()) {
-        // Not visible, play time is running -> Start hidden play time if needed.
-        HiddenVideoStart();
-      }
-
       mDecoder->NotifyOwnerActivityChanged(false);
       break;
     }
     case Visibility::APPROXIMATELY_VISIBLE: {
-      // Visible -> Just pause hidden play time (no-op if already paused).
-      HiddenVideoStop();
-
       mDecoder->NotifyOwnerActivityChanged(true);
       break;
     }
@@ -6860,97 +6590,6 @@ HTMLMediaElement::MarkAsContentSource(CallerAPI aAPI)
 {
   const bool isVisible = mVisibilityState != Visibility::APPROXIMATELY_NONVISIBLE;
 
-  if (isVisible) {
-    // 0 = ALL_VISIBLE
-    Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE, 0);
-  } else {
-    // 1 = ALL_INVISIBLE
-    Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE, 1);
-
-    if (IsInUncomposedDoc()) {
-      // 0 = ALL_IN_TREE
-      Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE_IN_TREE_OR_NOT, 0);
-    } else {
-      // 1 = ALL_NOT_IN_TREE
-      Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE_IN_TREE_OR_NOT, 1);
-    }
-  }
-
-  switch (aAPI) {
-    case CallerAPI::DRAW_IMAGE: {
-      if (isVisible) {
-        // 2 = drawImage_VISIBLE
-        Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE, 2);
-      } else {
-        // 3 = drawImage_INVISIBLE
-        Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE, 3);
-
-        if (IsInUncomposedDoc()) {
-          // 2 = drawImage_IN_TREE
-          Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE_IN_TREE_OR_NOT, 2);
-        } else {
-          // 3 = drawImage_NOT_IN_TREE
-          Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE_IN_TREE_OR_NOT, 3);
-        }
-      }
-      break;
-    }
-    case CallerAPI::CREATE_PATTERN: {
-      if (isVisible) {
-        // 4 = createPattern_VISIBLE
-        Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE, 4);
-      } else {
-        // 5 = createPattern_INVISIBLE
-        Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE, 5);
-
-        if (IsInUncomposedDoc()) {
-          // 4 = createPattern_IN_TREE
-          Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE_IN_TREE_OR_NOT, 4);
-        } else {
-          // 5 = createPattern_NOT_IN_TREE
-          Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE_IN_TREE_OR_NOT, 5);
-        }
-      }
-      break;
-    }
-    case CallerAPI::CREATE_IMAGEBITMAP: {
-      if (isVisible) {
-        // 6 = createImageBitmap_VISIBLE
-        Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE, 6);
-      } else {
-        // 7 = createImageBitmap_INVISIBLE
-        Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE, 7);
-
-        if (IsInUncomposedDoc()) {
-          // 6 = createImageBitmap_IN_TREE
-          Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE_IN_TREE_OR_NOT, 6);
-        } else {
-          // 7 = createImageBitmap_NOT_IN_TREE
-          Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE_IN_TREE_OR_NOT, 7);
-        }
-      }
-      break;
-    }
-    case CallerAPI::CAPTURE_STREAM: {
-      if (isVisible) {
-        // 8 = captureStream_VISIBLE
-        Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE, 8);
-      } else {
-        // 9 = captureStream_INVISIBLE
-        Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE, 9);
-
-        if (IsInUncomposedDoc()) {
-          // 8 = captureStream_IN_TREE
-          Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE_IN_TREE_OR_NOT, 8);
-        } else {
-          // 9 = captureStream_NOT_IN_TREE
-          Telemetry::Accumulate(Telemetry::VIDEO_AS_CONTENT_SOURCE_IN_TREE_OR_NOT, 9);
-        }
-      }
-      break;
-    }
-  }
-
   LOG(LogLevel::Debug,
       ("%p Log VIDEO_AS_CONTENT_SOURCE: visibility = %u, API: '%d' and 'All'",
        this, isVisible, aAPI));
diff --git a/dom/html/HTMLMediaElement.h b/dom/html/HTMLMediaElement.h
index af944a318..899e8449a 100644
--- a/dom/html/HTMLMediaElement.h
+++ b/dom/html/HTMLMediaElement.h
@@ -1195,29 +1195,6 @@ protected:
     return isPaused;
   }
 
-  /**
-   * Video has been playing while hidden and, if feature was enabled, would
-   * trigger suspending decoder.
-   * Used to track hidden-video-decode-suspend telemetry.
-   */
-  static void VideoDecodeSuspendTimerCallback(nsITimer* aTimer, void* aClosure);
-  /**
-   * Video is now both: playing and hidden.
-   * Used to track hidden-video telemetry.
-   */
-  void HiddenVideoStart();
-  /**
-   * Video is not playing anymore and/or has become visible.
-   * Used to track hidden-video telemetry.
-   */
-  void HiddenVideoStop();
-
-#ifdef MOZ_EME
-  void ReportEMETelemetry();
-#endif
-
-  void ReportTelemetry();
-
   // Check the permissions for audiochannel.
   bool CheckAudioChannelPermissions(const nsAString& aType);
 
@@ -1484,9 +1461,6 @@ protected:
   // Timer used for updating progress events.
   nsCOMPtr<nsITimer> mProgressTimer;
 
-  // Timer used to simulate video-suspend.
-  nsCOMPtr<nsITimer> mVideoDecodeSuspendTimer;
-
 #ifdef MOZ_EME
   // Encrypted Media Extension media keys.
   RefPtr<MediaKeys> mMediaKeys;
@@ -1688,65 +1662,7 @@ protected:
   // before attaching to the DOM tree.
   bool mUnboundFromTree = false;
 
-public:
-  // Helper class to measure times for MSE telemetry stats
-  class TimeDurationAccumulator
-  {
-  public:
-    TimeDurationAccumulator()
-      : mCount(0)
-    {}
-    void Start()
-    {
-      if (IsStarted()) {
-        return;
-      }
-      mStartTime = TimeStamp::Now();
-    }
-    void Pause()
-    {
-      if (!IsStarted()) {
-        return;
-      }
-      mSum += (TimeStamp::Now() - mStartTime);
-      mCount++;
-      mStartTime = TimeStamp();
-    }
-    bool IsStarted() const
-    {
-      return !mStartTime.IsNull();
-    }
-    double Total() const
-    {
-      if (!IsStarted()) {
-        return mSum.ToSeconds();
-      }
-      // Add current running time until now, but keep it running.
-      return (mSum + (TimeStamp::Now() - mStartTime)).ToSeconds();
-    }
-    uint32_t Count() const
-    {
-      if (!IsStarted()) {
-        return mCount;
-      }
-      // Count current run in this report, without increasing the stored count.
-      return mCount + 1;
-    }
-  private:
-    TimeStamp mStartTime;
-    TimeDuration mSum;
-    uint32_t mCount;
-  };
 private:
-  // Total time a video has spent playing.
-  TimeDurationAccumulator mPlayTime;
-
-  // Total time a video has spent playing while hidden.
-  TimeDurationAccumulator mHiddenPlayTime;
-
-  // Total time a video has (or would have) spent in video-decode-suspend mode.
-  TimeDurationAccumulator mVideoDecodeSuspendTime;
-
   // Indicates if user has interacted with the element.
   // Used to block autoplay when disabled.
   bool mHasUserInteraction;
diff --git a/dom/html/HTMLOptionsCollection.cpp b/dom/html/HTMLOptionsCollection.cpp
index 294493c0c..67de97fc4 100644
--- a/dom/html/HTMLOptionsCollection.cpp
+++ b/dom/html/HTMLOptionsCollection.cpp
@@ -35,23 +35,8 @@ namespace mozilla {
 namespace dom {
 
 HTMLOptionsCollection::HTMLOptionsCollection(HTMLSelectElement* aSelect)
-{
-  // Do not maintain a reference counted reference. When
-  // the select goes away, it will let us know.
-  mSelect = aSelect;
-}
-
-HTMLOptionsCollection::~HTMLOptionsCollection()
-{
-  DropReference();
-}
-
-void
-HTMLOptionsCollection::DropReference()
-{
-  // Drop our (non ref-counted) reference
-  mSelect = nullptr;
-}
+  : mSelect(aSelect)
+{}
 
 nsresult
 HTMLOptionsCollection::GetOptionIndex(Element* aOption,
@@ -88,7 +73,9 @@ HTMLOptionsCollection::GetOptionIndex(Element* aOption,
 }
 
 
-NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(HTMLOptionsCollection, mElements)
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(HTMLOptionsCollection,
+                                      mElements,
+                                      mSelect)
 
 // nsISupports
 
@@ -124,10 +111,6 @@ HTMLOptionsCollection::GetLength(uint32_t* aLength)
 NS_IMETHODIMP
 HTMLOptionsCollection::SetLength(uint32_t aLength)
 {
-  if (!mSelect) {
-    return NS_ERROR_UNEXPECTED;
-  }
-
   return mSelect->SetLength(aLength);
 }
 
@@ -135,10 +118,6 @@ NS_IMETHODIMP
 HTMLOptionsCollection::SetOption(uint32_t aIndex,
                                  nsIDOMHTMLOptionElement* aOption)
 {
-  if (!mSelect) {
-    return NS_OK;
-  }
-
   // if the new option is null, just remove this option.  Note that it's safe
   // to pass a too-large aIndex in here.
   if (!aOption) {
@@ -187,11 +166,6 @@ HTMLOptionsCollection::SetOption(uint32_t aIndex,
 int32_t
 HTMLOptionsCollection::GetSelectedIndex(ErrorResult& aError)
 {
-  if (!mSelect) {
-    aError.Throw(NS_ERROR_UNEXPECTED);
-    return 0;
-  }
-
   int32_t selectedIndex;
   aError = mSelect->GetSelectedIndex(&selectedIndex);
   return selectedIndex;
@@ -209,11 +183,6 @@ void
 HTMLOptionsCollection::SetSelectedIndex(int32_t aSelectedIndex,
                                         ErrorResult& aError)
 {
-  if (!mSelect) {
-    aError.Throw(NS_ERROR_UNEXPECTED);
-    return;
-  }
-
   aError = mSelect->SetSelectedIndex(aSelectedIndex);
 }
 
@@ -339,22 +308,12 @@ HTMLOptionsCollection::Add(const HTMLOptionOrOptGroupElement& aElement,
                            const Nullable<HTMLElementOrLong>& aBefore,
                            ErrorResult& aError)
 {
-  if (!mSelect) {
-    aError.Throw(NS_ERROR_NOT_INITIALIZED);
-    return;
-  }
-
   mSelect->Add(aElement, aBefore, aError);
 }
 
 void
 HTMLOptionsCollection::Remove(int32_t aIndex, ErrorResult& aError)
 {
-  if (!mSelect) {
-    aError.Throw(NS_ERROR_UNEXPECTED);
-    return;
-  }
-
   uint32_t len = 0;
   mSelect->GetLength(&len);
   if (aIndex < 0 || (uint32_t)aIndex >= len)
diff --git a/dom/html/HTMLOptionsCollection.h b/dom/html/HTMLOptionsCollection.h
index 21123b3d2..496919555 100644
--- a/dom/html/HTMLOptionsCollection.h
+++ b/dom/html/HTMLOptionsCollection.h
@@ -46,7 +46,7 @@ public:
   using nsWrapperCache::GetWrapper;
   virtual JSObject* WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto) override;
 protected:
-  virtual ~HTMLOptionsCollection();
+  virtual ~HTMLOptionsCollection() = default;
 
   virtual JSObject* GetWrapperPreserveColorInternal() override
   {
@@ -113,11 +113,6 @@ public:
   }
 
   /**
-   * Drop the reference to the select.  Called during select destruction.
-   */
-  void DropReference();
-
-  /**
    * Finds the index of a given option element.
    * If the option isn't part of the collection, return NS_ERROR_FAILURE
    * without setting aIndex.
@@ -161,7 +156,7 @@ private:
    * various members such as InsertOptionAt are also infallible. */
   nsTArray<RefPtr<mozilla::dom::HTMLOptionElement> > mElements;
   /** The select element that contains this array */
-  HTMLSelectElement* mSelect;
+  RefPtr<HTMLSelectElement> mSelect;
 };
 
 } // namespace dom
diff --git a/dom/html/HTMLSelectElement.cpp b/dom/html/HTMLSelectElement.cpp
index 53f42317a..9ba0a1efe 100644
--- a/dom/html/HTMLSelectElement.cpp
+++ b/dom/html/HTMLSelectElement.cpp
@@ -130,11 +130,6 @@ HTMLSelectElement::HTMLSelectElement(already_AddRefed<mozilla::dom::NodeInfo>& a
                     NS_EVENT_STATE_VALID);
 }
 
-HTMLSelectElement::~HTMLSelectElement()
-{
-  mOptions->DropReference();
-}
-
 // ISupports
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(HTMLSelectElement)
diff --git a/dom/html/HTMLSelectElement.h b/dom/html/HTMLSelectElement.h
index 8a25385de..dc1075cd7 100644
--- a/dom/html/HTMLSelectElement.h
+++ b/dom/html/HTMLSelectElement.h
@@ -436,7 +436,7 @@ public:
   void SetOpenInParentProcess(bool aVal);
 
 protected:
-  virtual ~HTMLSelectElement();
+  virtual ~HTMLSelectElement() = default;
 
   friend class SafeOptionListMutation;
 
diff --git a/dom/html/HTMLTableElement.cpp b/dom/html/HTMLTableElement.cpp
index ec1b7cecb..c5b7696cf 100644
--- a/dom/html/HTMLTableElement.cpp
+++ b/dom/html/HTMLTableElement.cpp
@@ -421,11 +421,10 @@ HTMLTableElement::CreateTHead()
 void
 HTMLTableElement::DeleteTHead()
 {
-  HTMLTableSectionElement* tHead = GetTHead();
+  RefPtr<HTMLTableSectionElement> tHead = GetTHead();
   if (tHead) {
-    mozilla::ErrorResult rv;
+    mozilla::IgnoredErrorResult rv;
     nsINode::RemoveChild(*tHead, rv);
-    MOZ_ASSERT(!rv.Failed());
   }
 }
 
@@ -452,11 +451,10 @@ HTMLTableElement::CreateTFoot()
 void
 HTMLTableElement::DeleteTFoot()
 {
-  HTMLTableSectionElement* tFoot = GetTFoot();
+  RefPtr<HTMLTableSectionElement> tFoot = GetTFoot();
   if (tFoot) {
-    mozilla::ErrorResult rv;
+    mozilla::IgnoredErrorResult rv;
     nsINode::RemoveChild(*tFoot, rv);
-    MOZ_ASSERT(!rv.Failed());
   }
 }
 
@@ -483,11 +481,10 @@ HTMLTableElement::CreateCaption()
 void
 HTMLTableElement::DeleteCaption()
 {
-  HTMLTableCaptionElement* caption = GetCaption();
+  RefPtr<HTMLTableCaptionElement> caption = GetCaption();
   if (caption) {
-    mozilla::ErrorResult rv;
+    mozilla::IgnoredErrorResult rv;
     nsINode::RemoveChild(*caption, rv);
-    MOZ_ASSERT(!rv.Failed());
   }
 }
 
diff --git a/dom/html/HTMLTableSectionElement.cpp b/dom/html/HTMLTableSectionElement.cpp
index c7b0665dd..e99597636 100644
--- a/dom/html/HTMLTableSectionElement.cpp
+++ b/dom/html/HTMLTableSectionElement.cpp
@@ -122,7 +122,7 @@ HTMLTableSectionElement::DeleteRow(int32_t aValue, ErrorResult& aError)
     refIndex = (uint32_t)aValue;
   }
 
-  nsINode* row = rows->Item(refIndex);
+  nsCOMPtr<nsINode> row = rows->Item(refIndex);
   if (!row) {
     aError.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);
     return;
diff --git a/dom/html/ImageDocument.cpp b/dom/html/ImageDocument.cpp
index 200bb5d46..451d989c3 100644
--- a/dom/html/ImageDocument.cpp
+++ b/dom/html/ImageDocument.cpp
@@ -40,12 +40,14 @@
 #include "nsThreadUtils.h"
 #include "nsIScrollableFrame.h"
 #include "nsContentUtils.h"
+#include "nsCSSParser.h" // for CSS colors on the background
 #include "mozilla/dom/Element.h"
 #include "mozilla/Preferences.h"
 #include <algorithm>
 
 #define AUTOMATIC_IMAGE_RESIZING_PREF "browser.enable_automatic_image_resizing"
 #define CLICK_IMAGE_RESIZING_PREF "browser.enable_click_image_resizing"
+#define STANDALONE_IMAGE_BACKGROUND_COLOR_PREF "browser.display.standalone_images.background_color"
 //XXX A hack needed for Firefox's site specific zoom.
 #define SITE_SPECIFIC_ZOOM "browser.zoom.siteSpecific"
 
@@ -170,6 +172,8 @@ ImageDocument::Init()
   mClickResizingEnabled = Preferences::GetBool(CLICK_IMAGE_RESIZING_PREF);
   mShouldResize = mResizeImageByDefault;
   mFirstResize = true;
+  
+  mBackgroundColor = Preferences::GetString(STANDALONE_IMAGE_BACKGROUND_COLOR_PREF);
 
   return NS_OK;
 }
@@ -655,7 +659,7 @@ ImageDocument::CreateSyntheticDocument()
   NS_ENSURE_SUCCESS(rv, rv);
 
   // Add the image element
-  Element* body = GetBodyElement();
+  RefPtr<Element> body = GetBodyElement();
   if (!body) {
     NS_WARNING("no body on image document!");
     return NS_ERROR_FAILURE;
@@ -682,9 +686,22 @@ ImageDocument::CreateSyntheticDocument()
   mImageContent->SetAttr(kNameSpaceID_None, nsGkAtoms::src, srcString, false);
   mImageContent->SetAttr(kNameSpaceID_None, nsGkAtoms::alt, srcString, false);
 
+  // Implement mechanism for custom background color from pref.
+  if (!mBackgroundColor.IsEmpty()) {
+    nsCSSValue color;
+    nsCSSParser parser;
+    if (parser.ParseColorString(mBackgroundColor, nullptr, 0, color)) {
+      nsAutoString styleAttr(NS_LITERAL_STRING("background-color: "));
+      styleAttr.Append(mBackgroundColor);
+      body->SetAttr(kNameSpaceID_None, nsGkAtoms::style, styleAttr, false);
+    }
+  }
+
   body->AppendChildTo(mImageContent, false);
   imageLoader->SetLoadingEnabled(true);
 
+  UpdateTitleAndCharset();
+  
   return NS_OK;
 }
 
diff --git a/dom/html/ImageDocument.h b/dom/html/ImageDocument.h
index fdf2a00a8..945317314 100644
--- a/dom/html/ImageDocument.h
+++ b/dom/html/ImageDocument.h
@@ -112,6 +112,9 @@ protected:
   float                         mVisibleHeight;
   int32_t                       mImageWidth;
   int32_t                       mImageHeight;
+  
+  // Holds the custom background color for stand-alone images
+  nsAutoString                  mBackgroundColor;
 
   bool                          mResizeImageByDefault;
   bool                          mClickResizingEnabled;
diff --git a/dom/html/PluginDocument.cpp b/dom/html/PluginDocument.cpp
index 1c923ecc6..f6be8a915 100644
--- a/dom/html/PluginDocument.cpp
+++ b/dom/html/PluginDocument.cpp
@@ -206,7 +206,7 @@ PluginDocument::CreateSyntheticPluginDocument()
   NS_ENSURE_SUCCESS(rv, rv);
   // then attach our plugin
 
-  Element* body = GetBodyElement();
+  RefPtr<Element> body = GetBodyElement();
   if (!body) {
     NS_WARNING("no body on plugin document!");
     return NS_ERROR_FAILURE;
diff --git a/dom/html/TextTrackManager.cpp b/dom/html/TextTrackManager.cpp
index 8110dab29..7f9d32794 100644
--- a/dom/html/TextTrackManager.cpp
+++ b/dom/html/TextTrackManager.cpp
@@ -12,7 +12,6 @@
 #include "mozilla/dom/TextTrackCue.h"
 #include "mozilla/dom/Event.h"
 #include "mozilla/ClearOnShutdown.h"
-#include "mozilla/Telemetry.h"
 #include "nsComponentManagerUtils.h"
 #include "nsVariant.h"
 #include "nsVideoFrame.h"
@@ -30,6 +29,13 @@ namespace dom {
 
 NS_IMPL_ISUPPORTS(TextTrackManager::ShutdownObserverProxy, nsIObserver);
 
+void
+TextTrackManager::ShutdownObserverProxy::Unregister()
+{
+  nsContentUtils::UnregisterShutdownObserver(this);
+  mManager = nullptr;
+}
+
 CompareTextTracks::CompareTextTracks(HTMLMediaElement* aMediaElement)
 {
   mMediaElement = aMediaElement;
@@ -112,7 +118,6 @@ TextTrackManager::TextTrackManager(HTMLMediaElement *aMediaElement)
   , mTimeMarchesOnDispatched(false)
   , mUpdateCueDisplayDispatched(false)
   , performedTrackSelection(false)
-  , mCueTelemetryReported(false)
   , mShutdown(false)
 {
   nsISupports* parentObject =
@@ -138,7 +143,7 @@ TextTrackManager::TextTrackManager(HTMLMediaElement *aMediaElement)
 TextTrackManager::~TextTrackManager()
 {
   WEBVTT_LOG("%p ~TextTrackManager",this);
-  nsContentUtils::UnregisterShutdownObserver(mShutdownProxy);
+  mShutdownProxy->Unregister();
 }
 
 TextTrackList*
@@ -164,7 +169,6 @@ TextTrackManager::AddTextTrack(TextTrackKind aKind, const nsAString& aLabel,
     mTextTracks->AddTextTrack(aKind, aLabel, aLanguage, aMode, aReadyState,
                               aTextTrackSource, CompareTextTracks(mMediaElement));
   AddCues(track);
-  ReportTelemetryForTrack(track);
 
   if (aTextTrackSource == TextTrackSource::Track) {
     RefPtr<nsIRunnable> task =
@@ -184,7 +188,6 @@ TextTrackManager::AddTextTrack(TextTrack* aTextTrack)
   WEBVTT_LOG("%p AddTextTrack TextTrack %p",this, aTextTrack);
   mTextTracks->AddTextTrack(aTextTrack, CompareTextTracks(mMediaElement));
   AddCues(aTextTrack);
-  ReportTelemetryForTrack(aTextTrack);
 
   if (aTextTrack->GetTextTrackSource() == TextTrackSource::Track) {
     RefPtr<nsIRunnable> task =
@@ -303,7 +306,6 @@ TextTrackManager::NotifyCueAdded(TextTrackCue& aCue)
     mNewCues->AddCue(aCue);
   }
   DispatchTimeMarchesOn();
-  ReportTelemetryForCue();
 }
 
 void
@@ -821,28 +823,5 @@ TextTrackManager::NotifyReset()
   mLastTimeMarchesOnCalled = 0.0;
 }
 
-void
-TextTrackManager::ReportTelemetryForTrack(TextTrack* aTextTrack) const
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  MOZ_ASSERT(aTextTrack);
-  MOZ_ASSERT(mTextTracks->Length() > 0);
-
-  TextTrackKind kind = aTextTrack->Kind();
-  Telemetry::Accumulate(Telemetry::WEBVTT_TRACK_KINDS, uint32_t(kind));
-}
-
-void
-TextTrackManager::ReportTelemetryForCue()
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  MOZ_ASSERT(!mNewCues->IsEmpty() || !mLastActiveCues->IsEmpty());
-
-  if (!mCueTelemetryReported) {
-    Telemetry::Accumulate(Telemetry::WEBVTT_USED_VTT_CUES, 1);
-    mCueTelemetryReported = true;
-  }
-}
-
 } // namespace dom
 } // namespace mozilla
diff --git a/dom/html/TextTrackManager.h b/dom/html/TextTrackManager.h
index d20707346..2375aa4bb 100644
--- a/dom/html/TextTrackManager.h
+++ b/dom/html/TextTrackManager.h
@@ -148,13 +148,6 @@ private:
                            nsTArray<TextTrack*>& aTextTracks);
   bool TrackIsDefault(TextTrack* aTextTrack);
 
-  void ReportTelemetryForTrack(TextTrack* aTextTrack) const;
-  void ReportTelemetryForCue();
-
-  // If there is at least one cue has been added to the cue list once, we would
-  // report the usage of cue to Telemetry.
-  bool mCueTelemetryReported;
-
   class ShutdownObserverProxy final : public nsIObserver
   {
     NS_DECL_ISUPPORTS
@@ -170,11 +163,15 @@ private:
     {
       MOZ_ASSERT(NS_IsMainThread());
       if (strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0) {
-        nsContentUtils::UnregisterShutdownObserver(this);
-        mManager->NotifyShutdown();
+        if (mManager) {
+          mManager->NotifyShutdown();
+        }
+        Unregister();
       }
       return NS_OK;
     }
+    
+    void Unregister();
 
   private:
     ~ShutdownObserverProxy() {};
diff --git a/dom/html/VideoDocument.cpp b/dom/html/VideoDocument.cpp
index 1bd898564..76b2e326f 100644
--- a/dom/html/VideoDocument.cpp
+++ b/dom/html/VideoDocument.cpp
@@ -90,7 +90,7 @@ VideoDocument::CreateSyntheticVideoDocument(nsIChannel* aChannel,
   nsresult rv = MediaDocument::CreateSyntheticDocument();
   NS_ENSURE_SUCCESS(rv, rv);
 
-  Element* body = GetBodyElement();
+  RefPtr<Element> body = GetBodyElement();
   if (!body) {
     NS_WARNING("no body on video document!");
     return NS_ERROR_FAILURE;
diff --git a/dom/html/nsDOMStringMap.cpp b/dom/html/nsDOMStringMap.cpp
index 42725bc6f..6d2bc424d 100644
--- a/dom/html/nsDOMStringMap.cpp
+++ b/dom/html/nsDOMStringMap.cpp
@@ -19,7 +19,6 @@ using namespace mozilla::dom;
 NS_IMPL_CYCLE_COLLECTION_CLASS(nsDOMStringMap)
 
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsDOMStringMap)
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_SCRIPT_OBJECTS
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mElement)
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
diff --git a/dom/html/nsGenericHTMLElement.h b/dom/html/nsGenericHTMLElement.h
index 0635c27e1..24a7a3652 100644
--- a/dom/html/nsGenericHTMLElement.h
+++ b/dom/html/nsGenericHTMLElement.h
@@ -396,13 +396,6 @@ public:
   }
   NS_IMETHOD InsertAdjacentHTML(const nsAString& position,
                                 const nsAString& text) final override;
-  NS_IMETHOD ScrollIntoView(bool top, uint8_t _argc) final override {
-    if (!_argc) {
-      top = true;
-    }
-    mozilla::dom::Element::ScrollIntoView(top);
-    return NS_OK;
-  }
   NS_IMETHOD GetOffsetParent(nsIDOMElement** aOffsetParent)
     final override {
     mozilla::dom::Element* offsetParent = GetOffsetParent();
diff --git a/dom/html/nsTextEditorState.cpp b/dom/html/nsTextEditorState.cpp
index 187afb66d..25be6016c 100644
--- a/dom/html/nsTextEditorState.cpp
+++ b/dom/html/nsTextEditorState.cpp
@@ -47,7 +47,6 @@
 #include "mozilla/dom/HTMLInputElement.h"
 #include "nsNumberControlFrame.h"
 #include "nsFrameSelection.h"
-#include "mozilla/Telemetry.h"
 #include "mozilla/layers/ScrollInputMethods.h"
 
 using namespace mozilla;
@@ -585,9 +584,6 @@ nsTextInputSelectionImpl::CompleteScroll(bool aForward)
   if (!mScrollFrame)
     return NS_ERROR_NOT_INITIALIZED;
 
-  mozilla::Telemetry::Accumulate(mozilla::Telemetry::SCROLL_INPUT_METHODS,
-      (uint32_t) ScrollInputMethod::MainThreadCompleteScroll);
-
   mScrollFrame->ScrollBy(nsIntPoint(0, aForward ? 1 : -1),
                          nsIScrollableFrame::WHOLE,
                          nsIScrollableFrame::INSTANT);
@@ -640,9 +636,6 @@ nsTextInputSelectionImpl::ScrollPage(bool aForward)
   if (!mScrollFrame)
     return NS_ERROR_NOT_INITIALIZED;
 
-  mozilla::Telemetry::Accumulate(mozilla::Telemetry::SCROLL_INPUT_METHODS,
-      (uint32_t) ScrollInputMethod::MainThreadScrollPage);
-
   mScrollFrame->ScrollBy(nsIntPoint(0, aForward ? 1 : -1),
                          nsIScrollableFrame::PAGES,
                          nsIScrollableFrame::SMOOTH);
@@ -655,9 +648,6 @@ nsTextInputSelectionImpl::ScrollLine(bool aForward)
   if (!mScrollFrame)
     return NS_ERROR_NOT_INITIALIZED;
 
-  mozilla::Telemetry::Accumulate(mozilla::Telemetry::SCROLL_INPUT_METHODS,
-      (uint32_t) ScrollInputMethod::MainThreadScrollLine);
-
   mScrollFrame->ScrollBy(nsIntPoint(0, aForward ? 1 : -1),
                          nsIScrollableFrame::LINES,
                          nsIScrollableFrame::SMOOTH);
@@ -670,9 +660,6 @@ nsTextInputSelectionImpl::ScrollCharacter(bool aRight)
   if (!mScrollFrame)
     return NS_ERROR_NOT_INITIALIZED;
 
-  mozilla::Telemetry::Accumulate(mozilla::Telemetry::SCROLL_INPUT_METHODS,
-      (uint32_t) ScrollInputMethod::MainThreadScrollCharacter);
-
   mScrollFrame->ScrollBy(nsIntPoint(aRight ? 1 : -1, 0),
                          nsIScrollableFrame::LINES,
                          nsIScrollableFrame::SMOOTH);
@@ -2268,7 +2255,11 @@ nsTextEditorState::UpdatePlaceholderText(bool aNotify)
 
   nsCOMPtr<nsIContent> content = do_QueryInterface(mTextCtrlElement);
   content->GetAttr(kNameSpaceID_None, nsGkAtoms::placeholder, placeholderValue);
-  nsContentUtils::RemoveNewlines(placeholderValue);
+  if (mTextCtrlElement->IsTextArea()) { // <textarea>s preserve newlines...
+    nsContentUtils::PlatformToDOMLineBreaks(placeholderValue);
+  } else { // ...<input>s don't
+    nsContentUtils::RemoveNewlines(placeholderValue);
+  }
   NS_ASSERTION(mPlaceholderDiv->GetFirstChild(), "placeholder div has no child");
   mPlaceholderDiv->GetFirstChild()->SetText(placeholderValue, aNotify);
 }
diff --git a/dom/html/test/mochitest.ini b/dom/html/test/mochitest.ini
index 0c0ba847c..1059bc5d0 100644
--- a/dom/html/test/mochitest.ini
+++ b/dom/html/test/mochitest.ini
@@ -553,7 +553,6 @@ skip-if = true # Disabled for timeouts.
 [test_viewport.html]
 [test_documentAll.html]
 [test_document-element-inserted.html]
-[test_document.watch.html]
 [test_bug445004.html]
 skip-if = true || toolkit == 'android' # Disabled permanently (bug 559932).
 [test_bug446483.html]
diff --git a/dom/html/test/test_document.watch.html b/dom/html/test/test_document.watch.html
deleted file mode 100644
index 54509823b..000000000
--- a/dom/html/test/test_document.watch.html
+++ /dev/null
@@ -1,129 +0,0 @@
-<!DOCTYPE html>
-<html>
-<!--
-https://bugzilla.mozilla.org/show_bug.cgi?id=903332
--->
-<head>
-  <meta charset="utf-8">
-  <title>Test for Bug 903332</title>
-  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
-  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
-  <script type="application/javascript">
-
-  /** Test for Bug 903332 **/
-
-  var watch1Called;
-  function watch1(prop, oldValue, newValue)
-  {
-    is(watch1Called, false, "watch1Called not reset properly?");
-    watch1Called = true;
-
-    is(prop, "cookie", "wrong property name passed to watch1");
-    return newValue;
-  }
-
-  var watch2Called;
-  function watch2(prop, oldValue, newValue)
-  {
-    is(watch2Called, false, "watch2Called not reset properly?");
-    watch2Called = true;
-
-    is(prop, "cookie", "wrong property name passed to watch2");
-    return newValue;
-  }
-
-  // Just in case subsequent tests depend on a particular value...
-  var originalValue = document.cookie;
-  ok(true, "originalValue: " + originalValue);
-
-  var originalPrefix = originalValue.length > 0 ? originalValue + "; " : "";
-
-  try
-  {
-    // trial set (no watch) to verify things work
-    document.cookie = "first=set";
-    is(document.cookie, originalPrefix + "first=set",
-       "first value correct");
-
-    // add a watch
-    document.watch("cookie", watch1);
-
-    // set, check for watch invoked
-    watch1Called = false;
-    document.cookie = "second=set";
-    is(watch1Called, true, "watch1 function should be called");
-    is(document.cookie, originalPrefix + "first=set; second=set",
-       "second value correct");
-
-    // and a second time, just in case
-    watch1Called = false;
-    document.cookie = "third=set";
-    is(watch1Called, true, "watch1 function should be called");
-    is(document.cookie, originalPrefix + "first=set; second=set; third=set",
-       "third value correct");
-
-    // overwrite the current watch with a new one
-    document.watch("cookie", watch2);
-
-    // set, check for watch invoked
-    watch1Called = false;
-    watch2Called = false;
-    document.cookie = "fourth=set";
-    is(watch1Called, false, "watch1 invoked erroneously");
-    is(watch2Called, true, "watch2 function should be called");
-    is(document.cookie, originalPrefix + "first=set; second=set; third=set; fourth=set",
-       "fourth value correct");
-
-    // and a second time, just in case
-    watch1Called = false;
-    watch2Called = false;
-    document.cookie = "fifth=set";
-    is(watch1Called, false, "watch1 invoked erroneously");
-    is(watch2Called, true, "watch2 function should be called");
-    is(document.cookie, originalPrefix + "first=set; second=set; third=set; fourth=set; fifth=set",
-       "fifth value correct");
-
-    // remove the watch
-    document.unwatch("cookie");
-
-    // check for non-invocation now
-    watch1Called = false;
-    watch2Called = false;
-    document.cookie = "sixth=set";
-    is(watch1Called, false, "watch1 shouldn't be called");
-    is(watch2Called, false, "watch2 shouldn't be called");
-    is(document.cookie, originalPrefix + "first=set; second=set; third=set; fourth=set; fifth=set; sixth=set",
-       "sixth value correct");
-  }
-  finally
-  {
-    // reset
-    document.unwatch("cookie"); // harmless, should be no-op except if bugs
-
-    var d = new Date();
-    d.setTime(0);
-    var suffix = "=; expires=" + d.toGMTString();
-
-    document.cookie = "first" + suffix;
-    document.cookie = "second" + suffix;
-    document.cookie = "third" + suffix;
-    document.cookie = "fourth" + suffix;
-    document.cookie = "fifth" + suffix;
-    document.cookie = "sixth" + suffix;
-  }
-
-  is(document.cookie, originalValue,
-     "document.cookie isn't what it was initially!  expect bustage further " +
-     "down the line");
-  </script>
-</head>
-<body>
-<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=903332">Mozilla Bug 903332</a>
-<p id="display"></p>
-<div id="content" style="display: none">
-
-</div>
-<pre id="test">
-</pre>
-</body>
-</html>