merge autoland to mozilla-central. r=merge a=merge

MozReview-Commit-ID: JWKcdNfAFqk
2017-09-13 11:25:59 +02:00 · 2017-09-13 11:25:59 +02:00 · dd669d05e1
--- a/browser/components/extensions/test/browser/browser_ext_devtools_panels_elements_sidebar.js
+++ b/browser/components/extensions/test/browser/browser_ext_devtools_panels_elements_sidebar.js
@ -7,6 +7,11 @@ XPCOMUtils.defineLazyModuleGetter(this, "gDevTools",
 XPCOMUtils.defineLazyModuleGetter(this, "devtools",
                                  "resource://devtools/shared/Loader.jsm");

+function isActiveSidebarTabTitle(inspector, expectedTabTitle, message) {
+  const actualTabTitle = inspector.panelDoc.querySelector(".tabs-menu-item.is-active").innerText;
+  is(actualTabTitle, expectedTabTitle, message);
+}
+
 add_task(async function test_devtools_panels_elements_sidebar() {
  let tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, "http://mochi.test:8888/");

@ -70,6 +75,9 @@ add_task(async function test_devtools_panels_elements_sidebar() {

  is(shownSidebarInstance, "sidebar1", "Got the shown event on the first extension sidebar");

+  isActiveSidebarTabTitle(inspector, "Test Sidebar 1",
+                          "Got the expected title on the active sidebar tab");
+
  const sidebarPanel1 = inspector.sidebar.getTabPanel(sidebarIds[0]);

  ok(sidebarPanel1, "Got a rendered sidebar panel for the first registered extension sidebar");
@ -94,6 +102,9 @@ add_task(async function test_devtools_panels_elements_sidebar() {
  is(shownSidebarInstance2, "sidebar2", "Got the shown event on the second extension sidebar");
  is(hiddenSidebarInstance1, "sidebar1", "Got the hidden event on the first extension sidebar");

+  isActiveSidebarTabTitle(inspector, "Test Sidebar 2",
+                          "Got the expected title on the active sidebar tab");
+
  const sidebarPanel2 = inspector.sidebar.getTabPanel(sidebarIds[1]);

  ok(sidebarPanel2, "Got a rendered sidebar panel for the second registered extension sidebar");
--- a/browser/themes/osx/browser.css
+++ b/browser/themes/osx/browser.css
@ -82,6 +82,7 @@
 }

 #main-window:not([tabsintitlebar]) > #titlebar {
+  -moz-appearance: -moz-window-titlebar;
  height: 22px; /* The native titlebar on OS X is 22px tall. */
 }

--- a/devtools/client/inspector/extensions/extension-sidebar.js
+++ b/devtools/client/inspector/extensions/extension-sidebar.js
@ -52,6 +52,7 @@ class ExtensionSidebar {
      this._provider = createElement(Provider, {
        store: this.store,
        key: this.id,
+        title: this.title,
      }, ExtensionSidebarComponent({
        id: this.id,
      }));
--- a/devtools/client/inspector/extensions/test/browser_inspector_extension_sidebar.js
+++ b/devtools/client/inspector/extensions/test/browser_inspector_extension_sidebar.js
@ -22,6 +22,8 @@ add_task(async function () {

  is(sidebar.title, sidebarTitle,
     "Got the expected title in the extension sidebar instance");
+  is(sidebar.provider.props.title, sidebarTitle,
+     "Got the expeted title in the provider props");

  let inspectorStoreState = inspector.store.getState();

--- a/dom/html/test/test_fullscreen-api.html
+++ b/dom/html/test/test_fullscreen-api.html
@ -77,15 +77,6 @@ function shouldSkipTest(test) {
      }
    }
  }
-  if (SpecialPowers.DOMWindowUtils.isStyledByServo &&
-      SpecialPowers.isDebugBuild &&
-      navigator.platform.indexOf('Mac') >= 0) {
-    if (test == "file_fullscreen-backdrop.html") {
-      todo(false, `${test} skipped due to bug 1387942`);
-      return true;
-    }
-  }
-
  return false;
 }

--- a/dom/media/MediaCache.cpp
+++ b/dom/media/MediaCache.cpp
@ -2156,6 +2156,13 @@ MediaCacheStream::GetLength()
  return mStreamLength;
 }

+int64_t
+MediaCacheStream::GetOffset() const
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  return mChannelOffset;
+}
+
 int64_t
 MediaCacheStream::GetNextCachedData(int64_t aOffset)
 {
--- a/dom/media/MediaCache.h
+++ b/dom/media/MediaCache.h
@ -285,6 +285,8 @@ public:
  // If we've successfully read data beyond the originally reported length,
  // we return the end of the data we've read.
  int64_t GetLength();
+  // Return the offset where next channel data will write to. Main thread only.
+  int64_t GetOffset() const;
  // Returns the unique resource ID. Call only on the main thread or while
  // holding the media cache lock.
  int64_t GetResourceID() { return mResourceID; }
--- a/dom/media/MediaResource.cpp
+++ b/dom/media/MediaResource.cpp
@ -80,7 +80,6 @@ ChannelMediaResource::ChannelMediaResource(MediaResourceCallback* aCallback,
                                           nsIURI* aURI,
                                           bool aIsPrivateBrowsing)
  : BaseMediaResource(aCallback, aChannel, aURI)
-  , mOffset(0)
  , mReopenOnError(false)
  , mCacheStream(this, aIsPrivateBrowsing)
  , mSuspendAgent(mChannel)
@ -93,7 +92,6 @@ ChannelMediaResource::ChannelMediaResource(
  nsIURI* aURI,
  const MediaChannelStatistics& aStatistics)
  : BaseMediaResource(aCallback, aChannel, aURI)
-  , mOffset(0)
  , mReopenOnError(false)
  , mCacheStream(this, /* aIsPrivateBrowsing = */ false)
  , mChannelStatistics(aStatistics)
@ -152,17 +150,20 @@ ChannelMediaResource::Listener::OnDataAvailable(nsIRequest* aRequest,
 }

 nsresult
-ChannelMediaResource::Listener::AsyncOnChannelRedirect(nsIChannel* aOldChannel,
-                                                       nsIChannel* aNewChannel,
-                                                       uint32_t aFlags,
-                                                       nsIAsyncVerifyRedirectCallback* cb)
+ChannelMediaResource::Listener::AsyncOnChannelRedirect(
+  nsIChannel* aOld,
+  nsIChannel* aNew,
+  uint32_t aFlags,
+  nsIAsyncVerifyRedirectCallback* cb)
 {
  nsresult rv = NS_OK;
-  if (mResource)
-    rv = mResource->OnChannelRedirect(aOldChannel, aNewChannel, aFlags);
+  if (mResource) {
+    rv = mResource->OnChannelRedirect(aOld, aNew, aFlags, mOffset);
+  }

-  if (NS_FAILED(rv))
+  if (NS_FAILED(rv)) {
    return rv;
+  }

  cb->OnRedirectVerifyCallback(NS_OK);
  return NS_OK;
@ -284,26 +285,19 @@ ChannelMediaResource::OnStartRequest(nsIRequest* aRequest)
        if (rangeTotal != -1) {
          contentLength = std::max(contentLength, rangeTotal);
        }
-        // Give some warnings if the ranges are unexpected.
-        // XXX These could be error conditions.
-        NS_WARNING_ASSERTION(
-          mOffset == rangeStart,
-          "response range start does not match current offset");
-        mOffset = rangeStart;
        mCacheStream.NotifyDataStarted(rangeStart);
      }
      acceptsRanges = gotRangeHeader;
-    } else if (mOffset > 0 && responseStatus == HTTP_OK_CODE) {
+    } else if (GetOffset() > 0 && responseStatus == HTTP_OK_CODE) {
      // If we get an OK response but we were seeking, or requesting a byte
      // range, then we have to assume that seeking doesn't work. We also need
      // to tell the cache that it's getting data for the start of the stream.
      mCacheStream.NotifyDataStarted(0);
-      mOffset = 0;

      // The server claimed it supported range requests.  It lied.
      acceptsRanges = false;
    }
-    if (mOffset == 0 && contentLength >= 0 &&
+    if (GetOffset() == 0 && contentLength >= 0 &&
        (responseStatus == HTTP_OK_CODE ||
         responseStatus == HTTP_PARTIAL_RESPONSE_CODE)) {
      mCacheStream.NotifyDataLength(contentLength);
@ -398,14 +392,14 @@ ChannelMediaResource::OnStopRequest(nsIRequest* aRequest, nsresult aStatus)
  // cause us to just re-read the stream, which would be really bad.
  if (mReopenOnError && aStatus != NS_ERROR_PARSED_DATA_CACHED &&
      aStatus != NS_BINDING_ABORTED &&
-      (mOffset == 0 || (GetLength() > 0 && mOffset != GetLength() &&
-                        mCacheStream.IsTransportSeekable()))) {
+      (GetOffset() == 0 || (GetLength() > 0 && GetOffset() != GetLength() &&
+                            mCacheStream.IsTransportSeekable()))) {
    // If the stream did close normally, restart the channel if we're either
    // at the start of the resource, or if the server is seekable and we're
    // not at the end of stream. We don't restart the stream if we're at the
    // end because not all web servers handle this case consistently; see:
    // https://bugzilla.mozilla.org/show_bug.cgi?id=1373618#c36
-    nsresult rv = CacheClientSeek(mOffset, false);
+    nsresult rv = CacheClientSeek(GetOffset(), false);
    if (NS_SUCCEEDED(rv)) {
      return rv;
    }
@ -430,12 +424,14 @@ ChannelMediaResource::OnStopRequest(nsIRequest* aRequest, nsresult aStatus)
 }

 nsresult
-ChannelMediaResource::OnChannelRedirect(nsIChannel* aOld, nsIChannel* aNew,
-                                        uint32_t aFlags)
+ChannelMediaResource::OnChannelRedirect(nsIChannel* aOld,
+                                        nsIChannel* aNew,
+                                        uint32_t aFlags,
+                                        int64_t aOffset)
 {
  mChannel = aNew;
  mSuspendAgent.NotifyChannelOpened(mChannel);
-  return SetupChannelHeaders();
+  return SetupChannelHeaders(aOffset);
 }

 nsresult
@ -444,11 +440,6 @@ ChannelMediaResource::CopySegmentToCache(nsIPrincipal* aPrincipal,
                                         uint32_t aCount,
                                         uint32_t* aWriteCount)
 {
-  // Keep track of where we're up to.
-  LOG("CopySegmentToCache at mOffset [%" PRId64 "] add "
-      "[%d] bytes for decoder[%p]",
-      mOffset, aCount, mCallback.get());
-  mOffset += aCount;
  mCacheStream.NotifyDataReceived(aCount, aFromSegment, aPrincipal);
  *aWriteCount = aCount;
  return NS_OK;
@ -528,25 +519,25 @@ ChannelMediaResource::Open(nsIStreamListener** aStreamListener)
    return rv;
  }

-  MOZ_ASSERT(mOffset == 0, "Who set mOffset already?");
-  mListener = new Listener(this);
+  MOZ_ASSERT(GetOffset() == 0, "Who set offset already?");
+  mListener = new Listener(this, 0);
  *aStreamListener = mListener;
  NS_ADDREF(*aStreamListener);
  return NS_OK;
 }

 nsresult
-ChannelMediaResource::OpenChannel()
+ChannelMediaResource::OpenChannel(int64_t aOffset)
 {
  MOZ_ASSERT(NS_IsMainThread());
  MOZ_ASSERT(mChannel);
  MOZ_ASSERT(!mListener, "Listener should have been removed by now");

-  mListener = new Listener(this);
+  mListener = new Listener(this, aOffset);
  nsresult rv = mChannel->SetNotificationCallbacks(mListener.get());
  NS_ENSURE_SUCCESS(rv, rv);

-  rv = SetupChannelHeaders();
+  rv = SetupChannelHeaders(aOffset);
  NS_ENSURE_SUCCESS(rv, rv);

  rv = mChannel->AsyncOpen2(mListener);
@ -561,7 +552,8 @@ ChannelMediaResource::OpenChannel()
  return NS_OK;
 }

-nsresult ChannelMediaResource::SetupChannelHeaders()
+nsresult
+ChannelMediaResource::SetupChannelHeaders(int64_t aOffset)
 {
  // Always use a byte range request even if we're reading from the start
  // of the resource.
@ -571,7 +563,7 @@ nsresult ChannelMediaResource::SetupChannelHeaders()
  if (hc) {
    // Use |mOffset| if seeking in a complete file download.
    nsAutoCString rangeString("bytes=");
-    rangeString.AppendInt(mOffset);
+    rangeString.AppendInt(aOffset);
    rangeString.Append('-');
    nsresult rv = hc->SetRequestHeader(NS_LITERAL_CSTRING("Range"), rangeString, false);
    NS_ENSURE_SUCCESS(rv, rv);
@ -584,7 +576,7 @@ nsresult ChannelMediaResource::SetupChannelHeaders()
    NS_ENSURE_TRUE(element, NS_ERROR_FAILURE);
    element->SetRequestHeaders(hc);
  } else {
-    NS_ASSERTION(mOffset == 0, "Don't know how to seek on this channel type");
+    NS_ASSERTION(aOffset == 0, "Don't know how to seek on this channel type");
    return NS_ERROR_FAILURE;
  }
  return NS_OK;
@ -754,10 +746,10 @@ void ChannelMediaResource::Resume()
      // the channel dead; if the media cache wants to read some other data
      // in the future, it will call CacheClientSeek itself which will reopen the
      // channel.
-      if (totalLength < 0 || mOffset < totalLength) {
+      if (totalLength < 0 || GetOffset() < totalLength) {
        // There is (or may be) data to read at mOffset, so start reading it.
        // Need to recreate the channel.
-        CacheClientSeek(mOffset, false);
+        CacheClientSeek(GetOffset(), false);
        element->DownloadResumed();
      } else {
        // The channel remains dead. Do not notify DownloadResumed() which
@ -863,8 +855,6 @@ ChannelMediaResource::CacheClientSeek(int64_t aOffset, bool aResume)

  CloseChannel();

-  mOffset = aOffset;
-
  if (aResume) {
    mSuspendAgent.Resume();
  }
@ -878,7 +868,7 @@ ChannelMediaResource::CacheClientSeek(int64_t aOffset, bool aResume)
  nsresult rv = RecreateChannel();
  NS_ENSURE_SUCCESS(rv, rv);

-  return OpenChannel();
+  return OpenChannel(aOffset);
 }

 nsresult
@ -962,6 +952,12 @@ ChannelMediaResource::GetLength()
  return mCacheStream.GetLength();
 }

+int64_t
+ChannelMediaResource::GetOffset() const
+{
+  return mCacheStream.GetOffset();
+}
+
 // ChannelSuspendAgent

 bool
--- a/dom/media/MediaResource.h
+++ b/dom/media/MediaResource.h
@ -510,7 +510,10 @@ public:
  {
    ~Listener() {}
  public:
-    explicit Listener(ChannelMediaResource* aResource) : mResource(aResource) {}
+    Listener(ChannelMediaResource* aResource, int64_t aOffset)
+      : mResource(aResource)
+      , mOffset(aOffset)
+    {}

    NS_DECL_ISUPPORTS
    NS_DECL_NSIREQUESTOBSERVER
@ -523,6 +526,7 @@ public:

  private:
    RefPtr<ChannelMediaResource> mResource;
+    const int64_t mOffset;
  };
  friend class Listener;

@ -536,17 +540,22 @@ protected:
  nsresult OnDataAvailable(nsIRequest* aRequest,
                           nsIInputStream* aStream,
                           uint32_t aCount);
-  nsresult OnChannelRedirect(nsIChannel* aOld, nsIChannel* aNew, uint32_t aFlags);
+  nsresult OnChannelRedirect(nsIChannel* aOld,
+                             nsIChannel* aNew,
+                             uint32_t aFlags,
+                             int64_t aOffset);

-  // Opens the channel, using an HTTP byte range request to start at mOffset
+  // Opens the channel, using an HTTP byte range request to start at aOffset
  // if possible. Main thread only.
-  nsresult OpenChannel();
+  nsresult OpenChannel(int64_t aOffset);
  nsresult RecreateChannel();
  // Add headers to HTTP request. Main thread only.
-  nsresult SetupChannelHeaders();
+  nsresult SetupChannelHeaders(int64_t aOffset);
  // Closes the channel. Main thread only.
  void CloseChannel();

+  int64_t GetOffset() const;
+
  // Parses 'Content-Range' header and returns results via parameters.
  // Returns error if header is not available, values are not parse-able or
  // values are out of range.
@ -568,7 +577,6 @@ protected:
                              uint32_t* aWriteCount);

  // Main thread access only
-  int64_t            mOffset;
  RefPtr<Listener> mListener;
  // When this flag is set, if we get a network error we should silently
  // reopen the stream.
--- a/gfx/layers/wr/StackingContextHelper.cpp
+++ b/gfx/layers/wr/StackingContextHelper.cpp
@ -14,6 +14,7 @@ namespace layers {

 StackingContextHelper::StackingContextHelper()
  : mBuilder(nullptr)
+  , mHasPerspectiveTransform(false)
  , mXScale(1.0f)
  , mYScale(1.0f)
 {
@ -26,6 +27,7 @@ StackingContextHelper::StackingContextHelper(const StackingContextHelper& aParen
                                             const Maybe<gfx::Matrix4x4>& aTransform,
                                             const nsTArray<wr::WrFilterOp>& aFilters)
  : mBuilder(&aBuilder)
+  , mHasPerspectiveTransform(false)
  , mXScale(1.0f)
  , mYScale(1.0f)
 {
@ -51,6 +53,7 @@ StackingContextHelper::StackingContextHelper(const StackingContextHelper& aParen
                                             gfx::Matrix4x4* aTransformPtr,
                                             const nsTArray<wr::WrFilterOp>& aFilters)
  : mBuilder(&aBuilder)
+  , mHasPerspectiveTransform(false)
  , mXScale(1.0f)
  , mYScale(1.0f)
 {
@ -83,6 +86,7 @@ StackingContextHelper::StackingContextHelper(const StackingContextHelper& aParen
                                             const nsTArray<wr::WrFilterOp>& aFilters,
                                             const gfx::CompositionOp& aMixBlendMode)
  : mBuilder(&aBuilder)
+  , mHasPerspectiveTransform(false)
  , mXScale(1.0f)
  , mYScale(1.0f)
 {
@ -92,6 +96,10 @@ StackingContextHelper::StackingContextHelper(const StackingContextHelper& aParen
    mTransform = *aTransformPtr;
  }

+  if (aPerspectivePtr) {
+    mHasPerspectiveTransform = true;
+  }
+
  bool is2d = !aTransformPtr || (aTransformPtr->Is2D() && !aPerspectivePtr);
  if (is2d) {
    nsRect itemBounds = aDisplayList->GetClippedBoundsWithRespectToASR(aDisplayListBuilder, aItem->GetActiveScrolledRoot());
@ -102,6 +110,7 @@ StackingContextHelper::StackingContextHelper(const StackingContextHelper& aParen
    mTransform.PostScale(aParentSC.mXScale, aParentSC.mYScale, 1.0);
    mTransform.NudgeToIntegersFixedEpsilon();

+    // Calculate the correct scale for current stacking context
    gfx::Size scale = mTransform.As2D().ScaleFactors(true);

    // Restore the scale to default if the scale is too small
@ -112,7 +121,7 @@ StackingContextHelper::StackingContextHelper(const StackingContextHelper& aParen

    mTransform.PreScale(1.0f/scale.width, 1.0f/scale.height, 1.0);

-    // Store the inherited scale if has
+    // Store the inherited scale for child
    this->mXScale = scale.width;
    this->mYScale = scale.height;
  } else {
--- a/gfx/layers/wr/StackingContextHelper.h
+++ b/gfx/layers/wr/StackingContextHelper.h
@ -83,13 +83,26 @@ public:
  // Same but rounds the rectangle to ints after transforming.
  wr::LayoutRect ToRelativeLayoutRectRounded(const LayoutDeviceRect& aRect) const;

+  // Export the inherited scale
+  gfx::Size GetInheritedScale() const {
+    return gfx::Size(mXScale, mYScale);
+  }
+
+  // Provide interface to setup the inherited scale to support
+  // special cases, like OMTA
+  void SetInheritedScale(const gfx::Size& aScale) {
+    mXScale = aScale.width;
+    mYScale = aScale.height;
+  }
+
  bool IsBackfaceVisible() const { return mTransform.IsBackfaceVisible(); }
+  bool HasPerspectiveTransform() const { return mHasPerspectiveTransform; }

 private:
  wr::DisplayListBuilder* mBuilder;
  LayerPoint mOrigin;
  gfx::Matrix4x4 mTransform;
-
+  bool mHasPerspectiveTransform;
  float mXScale;
  float mYScale;
 };
--- a/layout/base/ServoRestyleManager.cpp
+++ b/layout/base/ServoRestyleManager.cpp
@ -556,8 +556,10 @@ UpdateBackdropIfNeeded(nsIFrame* aFrame,
                                        /* aPseudoElement = */ nullptr);

  // NOTE(emilio): We can't use the changes handled for the owner of the
-  // backdrop frame, since it's out of flow, and parented to the viewport frame.
-  MOZ_ASSERT(backdropFrame->GetParent()->IsViewportFrame());
+  // backdrop frame, since it's out of flow, and parented to the viewport or
+  // canvas frame (depending on the `position` value).
+  MOZ_ASSERT(backdropFrame->GetParent()->IsViewportFrame() ||
+             backdropFrame->GetParent()->IsCanvasFrame());
  nsTArray<nsIFrame*> wrappersToRestyle;
  ServoRestyleState state(aStyleSet, aChangeList, wrappersToRestyle);
  aFrame->UpdateStyleOfOwnedChildFrame(backdropFrame, newContext, state);
--- a/layout/generic/nsTextFrame.cpp
+++ b/layout/generic/nsTextFrame.cpp
@ -6494,15 +6494,8 @@ nsTextFrame::PaintOneShadow(const PaintShadowParams& aParams,
  if (!shadowContext)
    return;

-  nscolor shadowColor;
-  const nscolor* decorationOverrideColor;
-  if (aShadowDetails->mHasColor) {
-    shadowColor = aShadowDetails->mColor;
-    decorationOverrideColor = &shadowColor;
-  } else {
-    shadowColor = aParams.foregroundColor;
-    decorationOverrideColor = nullptr;
-  }
+  nscolor shadowColor = aShadowDetails->mHasColor ? aShadowDetails->mColor
+                                                  : aParams.foregroundColor;

  if (aParams.textDrawer) {
    wr::TextShadow wrShadow;
@ -6538,7 +6531,8 @@ nsTextFrame::PaintOneShadow(const PaintShadowParams& aParams,
    aParams.context == shadowContext ? shadowColor : NS_RGB(0, 0, 0);
  params.clipEdges = aParams.clipEdges;
  params.drawSoftHyphen = (GetStateBits() & TEXT_HYPHEN_BREAK) != 0;
-  params.decorationOverrideColor = decorationOverrideColor;
+  // Multi-color shadow is not allowed, so we use the same color of the text color.
+  params.decorationOverrideColor = &params.textColor;
  DrawText(aParams.range, aParams.textBaselinePt + shadowOffset, params);

  contextBoxBlur.DoPaint();
--- a/layout/painting/nsDisplayList.cpp
+++ b/layout/painting/nsDisplayList.cpp
@ -7812,15 +7812,6 @@ nsDisplayTransform::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder& aBu
    // transform animation, the transform value will be resolved
    // after animation sampling on the compositor
    transformForSC = nullptr;
-
-    // Pass default transform to compositor in case gecko fails to
-    // get animated value after animation sampling.
-    OptionalTransform transformForCompositor = newTransformMatrix;
-
-    OpAddCompositorAnimations
-      anim(CompositorAnimations(animationInfo.GetAnimations(), animationsId),
-           transformForCompositor, void_t());
-    aManager->WrBridge()->AddWebRenderParentCommand(anim);
  }

  gfx::Matrix4x4Typed<LayerPixel, LayerPixel> boundTransform = ViewAs< gfx::Matrix4x4Typed<LayerPixel, LayerPixel> >(newTransformMatrix);
@ -7841,6 +7832,33 @@ nsDisplayTransform::CreateWebRenderCommands(mozilla::wr::DisplayListBuilder& aBu
                           nullptr,
                           filters);

+  if (animationsId) {
+    // Get the inheritedScale from parent and pass the scale to compositor
+    // to get correct sampling result
+    gfx::Size scale = aSc.GetInheritedScale();
+    for (layers::Animation& animation : animationInfo.GetAnimations()) {
+      if (animation.property() == eCSSProperty_transform) {
+        TransformData& transformData = animation.data().get_TransformData();
+        transformData.inheritedXScale() = scale.width;
+        transformData.inheritedYScale() = scale.height;
+        transformData.hasPerspectiveParent() = aSc.HasPerspectiveTransform();
+      }
+    }
+
+    // Pass default transform to compositor in case gecko fails to
+    // get animated value after animation sampling.
+    OptionalTransform transformForCompositor = newTransformMatrix;
+    OpAddCompositorAnimations
+      anim(CompositorAnimations(animationInfo.GetAnimations(), animationsId),
+           transformForCompositor, void_t());
+    aManager->WrBridge()->AddWebRenderParentCommand(anim);
+
+    // Since we passed a nullptr transformForSC to the StackingContextHelper,
+    // we now set up the correct inherited scale for the stacking context.
+    newTransformMatrix.PostScale(scale.width, scale.height, 1.0f);
+    sc.SetInheritedScale(newTransformMatrix.As2D().ScaleFactors(true));
+
+  }
  return mStoredList.CreateWebRenderCommands(aBuilder, sc, aParentCommands,
                                             aManager, aDisplayListBuilder);
 }
--- a/layout/reftests/bugs/reftest.list
+++ b/layout/reftests/bugs/reftest.list
@ -1651,11 +1651,13 @@ fuzzy-if(Android,8,300) fuzzy-if(skiaContent,1,40000) == 625409-1.html 625409-1-
 fuzzy-if(skiaContent,1,500) == 630835-1.html about:blank
 == 631352-1.html 631352-1-ref.html
 skip-if(!haveTestPlugin) fails-if(Android) fuzzy-if(winWidget&&!layersGPUAccelerated,102,535) fuzzy-if(skiaContent&&!Android,102,11000) HTTP == 632423-1.html 632423-1-ref.html
+pref(gfx.webrender.layers-free,true) skip-if(!webrender) == 632423-1.html 632423-1-ref.html
 skip-if(Android) random-if(winWidget||OSX==1010) == 632781-verybig.html 632781-ref.html
 == 632781-normalsize.html 632781-ref.html
 fuzzy-if(d2d&&/^Windows\x20NT\x206\.2/.test(http.oscpu),1,559) fuzzy-if(!isDebugBuild&&gtkWidget&&/^Linux\x20i686/.test(http.oscpu),102,140) == 633344-1.html 633344-1-ref.html # bug 1103623, Linux32 from GCC update
 fuzzy-if(skiaContent,1,500) == 634232-1.html 634232-1-ref.html
 fuzzy-if(skiaContent,3,120000) == 635302-1.html 635302-1-ref.html
+pref(gfx.webrender.layers-free,true) skip-if(!webrender) == 635302-1.html 635302-1-ref.html
 fuzzy(1,68) fuzzy-if(gtkWidget,1,70) fails-if(Android) fuzzy-if(skiaContent&&!Android,1,300) == 635373-1.html 635373-1-ref.html
 random-if(d2d) fails-if(Android) fuzzy-if(winWidget&&!d2d,20,118) fuzzy-if(skiaContent&&!Android,2,550) == 635373-2.html 635373-2-ref.html
 random-if(d2d) fails-if(Android) fuzzy-if(winWidget&&!d2d,20,116) fuzzy-if(skiaContent&&!Android,2,650) == 635373-3.html 635373-3-ref.html
--- a/layout/reftests/css-animations/reftest.list
+++ b/layout/reftests/css-animations/reftest.list
@ -43,6 +43,7 @@ fails == background-position-running.html background-position-ref.html # This te
 fails == background-position-important.html background-position-ref.html # This test fails the reftest-opaque-layer check since animating background-position overridden by a non-animated !important style also creates an active layer, and reftest-opaque-layer only handles items that are assigned to PaintedLayers.

 == mask-position-after-finish-1a.html mask-anim-ref.html
+pref(gfx.webrender.layers-free,true) skip-if(!webrender) == mask-position-after-finish-1a.html mask-anim-ref.html
 == mask-position-after-finish-1b.html mask-anim-ref.html
 == mask-position-in-delay-1a.html mask-anim-ref.html
 == mask-position-in-delay-1b.html mask-anim-ref.html
--- a/layout/reftests/image/reftest.list
+++ b/layout/reftests/image/reftest.list
@ -1,4 +1,5 @@
 fuzzy-if(Android,8,30) == background-image-zoom-1.html background-image-zoom-1-ref.html
+pref(gfx.webrender.layers-free,true) skip-if(!webrender) == background-image-zoom-1.html background-image-zoom-1-ref.html
 fails-if(usesRepeatResampling) == background-image-zoom-2.html about:blank
 == image-seam-1a.html image-seam-1-ref.html
 == image-seam-1b.html image-seam-1-ref.html
--- a/layout/reftests/invalidation/reftest.list
+++ b/layout/reftests/invalidation/reftest.list
@ -86,6 +86,7 @@ pref(layers.single-tile.enabled,false) != fast-scrolling.html about:blank
 == negative-w-component.html negative-w-component-ref.html

 == mask-invalidation-1a.html mask-invalidation-1-ref.html
+pref(gfx.webrender.layers-free,true) skip-if(!webrender) == mask-invalidation-1a.html mask-invalidation-1-ref.html
 == mask-invalidation-1b.html mask-invalidation-1-ref.html

 == mask-invalidation-2a.html mask-invalidation-2-ref.html
--- a/layout/reftests/text-shadow/decorations-multiple-zorder-ref.html
+++ b/layout/reftests/text-shadow/decorations-multiple-zorder-ref.html
@ -2,14 +2,23 @@

 <!-- Shadows -->
 <!-- Blue underline/text -->
-<div style="position: absolute; top: 22px; left: 22px; color: blue; text-decoration: underline;"><span style="color: rgba(0, 0, 0, 0);">testforquirks</span></div>
-<div style="position: absolute; top: 22px; left: 22px;"><span style="color: blue;">test</span></div>
+<div style="position: absolute; top: 22px; left: 22px;"><span style="color: blue; text-decoration: underline">test</span></div>
 <!-- Red overline/text -->
-<div style="position: absolute; top: 22px; left: 22px; color: rgba(0, 0, 0, 0);">test<span style="text-decoration: overline; color: red;"><span style="color: rgba(0, 0, 0, 0);">forquirks</span></span></div>
-<div style="position: absolute; top: 22px; left: 22px;"><span style="color: rgba(0, 0, 0, 0);">test</span><span style="color: red;">for</span></div>
+<!--
+There are some additional pixels appearing when two red texts are overlap. We
+use transparent color for the first one to prevent the situation and the failure 
+of reftest.
+-->
+<div style="position: absolute; top: 22px; left: 22px;"><span style="color: rgba(0, 0, 0, 0);">test</span><span style="color: transparent; text-decoration: red underline;">for</span></div>
+<div style="position: absolute; top: 22px; left: 22px;"><span style="color: rgba(0, 0, 0, 0);">test</span><span style="color: red; text-decoration: overline;">for</span></div>
 <!-- Green text/underline -->
-<div style="position: absolute; top: 22px; left: 22px;"><span style="color: rgba(0, 0, 0, 0);">testfor</span><span style="text-decoration: underline; color: green;"><span style="color: rgba(0, 0, 0, 0);">quirks</span></span></div>
-<div style="position: absolute; top: 22px; left: 22px;"><span style="color: rgba(0, 0, 0, 0);">testfor</span><span style="color: green;">quirks</span></div>
+<!--
+There are some additional pixels appearing when two red texts are overlap. We
+use transparent color for the first one to prevent the situation and the failure 
+of reftest.
+-->
+<div style="position: absolute; top: 22px; left: 22px;"><span style="color: rgba(0, 0, 0, 0);">testfor</span><span style="text-decoration: green underline; color: transparent;">quirks</span></div>
+<div style="position: absolute; top: 22px; left: 22px;"><span style="color: rgba(0, 0, 0, 0);">testfor</span><span style="text-decoration: overline; color: green;">quirks</span></div>

 <!-- "Real" text -->
 <!-- Blue underline/text -->
--- a/layout/reftests/transform/reftest.list
+++ b/layout/reftests/transform/reftest.list
@ -31,6 +31,7 @@ fuzzy-if(webrender,1,27) == compound-1a.html compound-1-ref.html
 == translate-1b.html translate-1-ref.html
 == translate-1c.html translate-1-ref.html
 == translate-1d.html translate-1-ref.html
+pref(gfx.webrender.layers-free,true) skip-if(!webrender) == translate-1d.html translate-1-ref.html
 == translate-1e.html translate-1-ref.html
 == translate-2a.html translate-2-ref.html
 == translate-3.html translate-3-ref.html
@ -46,6 +47,7 @@ random == rotate-1f.html rotate-1-ref.html
 # rotate: 90deg rotations should be indistinguishable from objects constructed
 # to look the same.
 == rotate-2a.html rotate-2-ref.html
+pref(gfx.webrender.layers-free,true) skip-if(!webrender) == rotate-2a.html rotate-2-ref.html
 == rotate-2b.html rotate-2-ref.html
 # -transform-origin: We should NOT get the same images when using different
 # -transform-origins.
--- a/mobile/android/base/java/org/mozilla/gecko/widget/AnimatedProgressBar.java
+++ b/mobile/android/base/java/org/mozilla/gecko/widget/AnimatedProgressBar.java
@ -162,14 +162,14 @@ public class AnimatedProgressBar extends ThemedProgressBar {
        } else {
            canvas.getClipBounds(mRect);
            final float clipWidth = mRect.width() * mClipRatio;
-            canvas.save();
+            final int saveCount = canvas.save();
            if (mIsRtl) {
                canvas.clipRect(mRect.left, mRect.top, mRect.right - clipWidth, mRect.bottom);
            } else {
                canvas.clipRect(mRect.left + clipWidth, mRect.top, mRect.right, mRect.bottom);
            }
            super.onDraw(canvas);
-            canvas.restore();
+            canvas.restoreToCount(saveCount);
        }
    }

@ -266,8 +266,11 @@ public class AnimatedProgressBar extends ThemedProgressBar {
        mClosingAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) {
-                mClipRatio = (float) valueAnimator.getAnimatedValue();
-                invalidate();
+                final float ratio = (float) valueAnimator.getAnimatedValue();
+                if (mClipRatio != ratio) {
+                    mClipRatio = ratio;
+                    invalidate();
+                }
            }
        });
        mClosingAnimator.addListener(new Animator.AnimatorListener() {
--- a/servo/Cargo.lock
+++ b/servo/Cargo.lock
@ -3587,7 +3587,7 @@ dependencies = [
 [[package]]
 name = "webrender"
 version = "0.50.0"
-source = "git+https://github.com/servo/webrender#3d58efaecdc5897de057beab57adc031bc2e187e"
+source = "git+https://github.com/servo/webrender#cd1855550857b910f752359b48c5cc053419c358"
 dependencies = [
 "app_units 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "bincode 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
@ -3615,7 +3615,7 @@ dependencies = [
 [[package]]
 name = "webrender_api"
 version = "0.50.0"
-source = "git+https://github.com/servo/webrender#3d58efaecdc5897de057beab57adc031bc2e187e"
+source = "git+https://github.com/servo/webrender#cd1855550857b910f752359b48c5cc053419c358"
 dependencies = [
 "app_units 0.5.6 (registry+https://github.com/rust-lang/crates.io-index)",
 "bincode 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
--- a/servo/components/style/cache.rs
+++ b/servo/components/style/cache.rs
@ -39,13 +39,22 @@ impl<K: Array> LRUCache<K> {
    #[inline]
    /// Touch a given entry, putting it first in the list.
    pub fn touch(&mut self, pos: usize) {
-        let last_index = self.entries.len() - 1;
-        if pos != last_index {
+        if pos != 0 {
            let entry = self.entries.remove(pos).unwrap();
            self.entries.push_front(entry);
        }
    }

+    /// Returns the front entry in the list (most recently used).
+    pub fn front(&self) -> Option<&K::Item> {
+        self.entries.get(0)
+    }
+
+    /// Returns a mutable reference to the front entry in the list (most recently used).
+    pub fn front_mut(&mut self) -> Option<&mut K::Item> {
+        self.entries.get_mut(0)
+    }
+
    /// Iterate over the contents of this cache, from more to less recently
    /// used.
    pub fn iter(&self) -> arraydeque::Iter<K::Item> {
--- a/servo/components/style/context.rs
+++ b/servo/components/style/context.rs
@ -26,7 +26,7 @@ use selectors::matching::ElementSelectorFlags;
 use servo_arc::Arc;
 #[cfg(feature = "servo")] use servo_atoms::Atom;
 use shared_lock::StylesheetGuards;
-use sharing::StyleSharingCandidateCache;
+use sharing::StyleSharingCache;
 use std::fmt;
 use std::ops;
 #[cfg(feature = "servo")] use std::sync::Mutex;
@ -679,7 +679,7 @@ impl StackLimitChecker {
 /// thread in order to be able to mutate it without locking.
 pub struct ThreadLocalStyleContext<E: TElement> {
    /// A cache to share style among siblings.
-    pub style_sharing_candidate_cache: StyleSharingCandidateCache<E>,
+    pub sharing_cache: StyleSharingCache<E>,
    /// The bloom filter used to fast-reject selector-matching.
    pub bloom_filter: StyleBloom<E>,
    /// A channel on which new animations that have been triggered by style
@ -716,7 +716,7 @@ impl<E: TElement> ThreadLocalStyleContext<E> {
    #[cfg(feature = "servo")]
    pub fn new(shared: &SharedStyleContext) -> Self {
        ThreadLocalStyleContext {
-            style_sharing_candidate_cache: StyleSharingCandidateCache::new(),
+            sharing_cache: StyleSharingCache::new(),
            bloom_filter: StyleBloom::new(),
            new_animations_sender: shared.local_context_creation_data.lock().unwrap().new_animations_sender.clone(),
            tasks: SequentialTaskList(Vec::new()),
@ -733,7 +733,7 @@ impl<E: TElement> ThreadLocalStyleContext<E> {
    /// Creates a new `ThreadLocalStyleContext` from a shared one.
    pub fn new(shared: &SharedStyleContext) -> Self {
        ThreadLocalStyleContext {
-            style_sharing_candidate_cache: StyleSharingCandidateCache::new(),
+            sharing_cache: StyleSharingCache::new(),
            bloom_filter: StyleBloom::new(),
            tasks: SequentialTaskList(Vec::new()),
            selector_flags: SelectorFlagsMap::new(),
--- a/servo/components/style/sharing/mod.rs
+++ b/servo/components/style/sharing/mod.rs
@ -68,7 +68,7 @@ use Atom;
 use applicable_declarations::ApplicableDeclarationBlock;
 use atomic_refcell::{AtomicRefCell, AtomicRefMut};
 use bloom::StyleBloom;
-use cache::{LRUCache, LRUCacheMutIterator};
+use cache::LRUCache;
 use context::{SelectorFlagsMap, SharedStyleContext, StyleContext};
 use data::ElementStyles;
 use dom::{TElement, SendElement};
@ -342,8 +342,8 @@ impl<E: TElement> StyleSharingTarget<E> {
    pub fn share_style_if_possible(
        &mut self,
        context: &mut StyleContext<E>,
-    ) -> StyleSharingResult {
-        let cache = &mut context.thread_local.style_sharing_candidate_cache;
+    ) -> Option<ElementStyles> {
+        let cache = &mut context.thread_local.sharing_cache;
        let shared_context = &context.shared;
        let selector_flags_map = &mut context.thread_local.selector_flags;
        let bloom_filter = &context.thread_local.bloom_filter;
@ -351,7 +351,7 @@ impl<E: TElement> StyleSharingTarget<E> {
        if cache.dom_depth != bloom_filter.matching_depth() {
            debug!("Can't share style, because DOM depth changed from {:?} to {:?}, element: {:?}",
                   cache.dom_depth, bloom_filter.matching_depth(), self.element);
-            return StyleSharingResult::CannotShare;
+            return None;
        }
        debug_assert_eq!(bloom_filter.current_parent(),
                         self.element.traversal_parent());
@ -370,45 +370,58 @@ impl<E: TElement> StyleSharingTarget<E> {
    }
 }

-/// A cache miss result.
-#[derive(Clone, Debug)]
-pub enum CacheMiss {
-    /// The parents don't match.
-    Parent,
-    /// One element was NAC, while the other wasn't.
-    NativeAnonymousContent,
-    /// The local name of the element and the candidate don't match.
-    LocalName,
-    /// The namespace of the element and the candidate don't match.
-    Namespace,
-    /// One of the element or the candidate was a link, but the other one
-    /// wasn't.
-    Link,
-    /// The element and the candidate match different kind of rules. This can
-    /// only happen in Gecko.
-    UserAndAuthorRules,
-    /// The element and the candidate are in a different state.
-    State,
-    /// The element had an id attribute, which qualifies for a unique style.
-    IdAttr,
-    /// The element had a style attribute, which qualifies for a unique style.
-    StyleAttr,
-    /// The element and the candidate class names didn't match.
-    Class,
-    /// The presentation hints didn't match.
-    PresHints,
-    /// The element and the candidate didn't match the same set of revalidation
-    /// selectors.
-    Revalidation,
+struct SharingCacheBase<Candidate> {
+    entries: LRUCache<[Candidate; SHARING_CACHE_BACKING_STORE_SIZE]>,
 }

-/// The results of attempting to share a style.
-pub enum StyleSharingResult {
-    /// We didn't find anybody to share the style with.
-    CannotShare,
-    /// The node's style can be shared. The integer specifies the index in the
-    /// LRU cache that was hit and the damage that was done.
-    StyleWasShared(usize, ElementStyles),
+impl<Candidate> Default for SharingCacheBase<Candidate> {
+    fn default() -> Self {
+        Self {
+            entries: LRUCache::new(),
+        }
+    }
+}
+
+impl<Candidate> SharingCacheBase<Candidate> {
+    fn clear(&mut self) {
+        self.entries.evict_all();
+    }
+
+    fn is_empty(&self) -> bool {
+        self.entries.num_entries() == 0
+    }
+}
+
+impl<E: TElement> SharingCache<E> {
+    fn insert(&mut self, el: E, validation_data_holder: &mut StyleSharingTarget<E>) {
+        self.entries.insert(StyleSharingCandidate {
+            element: el,
+            validation_data: validation_data_holder.take_validation_data(),
+        });
+    }
+
+    fn lookup<F>(&mut self, mut is_match: F) -> Option<ElementStyles>
+    where
+        F: FnMut(&mut StyleSharingCandidate<E>) -> bool
+    {
+        let mut index = None;
+        for (i, candidate) in self.entries.iter_mut().enumerate() {
+            if is_match(candidate) {
+                index = Some(i);
+                break;
+            }
+        };
+
+        match index {
+            None => None,
+            Some(i) => {
+                self.entries.touch(i);
+                let front = self.entries.front_mut().unwrap();
+                debug_assert!(is_match(front));
+                Some(front.element.borrow_data().unwrap().styles.clone())
+            }
+        }
+    }
 }

 /// Style sharing caches are are large allocations, so we store them in thread-local
@ -423,20 +436,19 @@ pub enum StyleSharingResult {
 ///
 /// [1] https://github.com/rust-lang/rust/issues/42763
 /// [2] https://github.com/rust-lang/rust/issues/13707
-type SharingCacheBase<Candidate> = LRUCache<[Candidate; SHARING_CACHE_BACKING_STORE_SIZE]>;
 type SharingCache<E> = SharingCacheBase<StyleSharingCandidate<E>>;
 type TypelessSharingCache = SharingCacheBase<FakeCandidate>;
 type StoredSharingCache = Arc<AtomicRefCell<TypelessSharingCache>>;

 thread_local!(static SHARING_CACHE_KEY: StoredSharingCache =
-              Arc::new(AtomicRefCell::new(LRUCache::new())));
+              Arc::new(AtomicRefCell::new(TypelessSharingCache::default())));

 /// An LRU cache of the last few nodes seen, so that we can aggressively try to
 /// reuse their styles.
 ///
 /// Note that this cache is flushed every time we steal work from the queue, so
 /// storing nodes here temporarily is safe.
-pub struct StyleSharingCandidateCache<E: TElement> {
+pub struct StyleSharingCache<E: TElement> {
    /// The LRU cache, with the type cast away to allow persisting the allocation.
    cache_typeless: OwningHandle<StoredSharingCache, AtomicRefMut<'static, TypelessSharingCache>>,
    /// Bind this structure to the lifetime of E, since that's what we effectively store.
@ -447,13 +459,14 @@ pub struct StyleSharingCandidateCache<E: TElement> {
    dom_depth: usize,
 }

-impl<E: TElement> Drop for StyleSharingCandidateCache<E> {
+impl<E: TElement> Drop for StyleSharingCache<E> {
    fn drop(&mut self) {
        self.clear();
    }
 }

-impl<E: TElement> StyleSharingCandidateCache<E> {
+impl<E: TElement> StyleSharingCache<E> {
+    #[allow(dead_code)]
    fn cache(&self) -> &SharingCache<E> {
        let base: &TypelessSharingCache = &*self.cache_typeless;
        unsafe { mem::transmute(base) }
@ -470,31 +483,25 @@ impl<E: TElement> StyleSharingCandidateCache<E> {
        assert_eq!(mem::align_of::<SharingCache<E>>(), mem::align_of::<TypelessSharingCache>());
        let cache_arc = SHARING_CACHE_KEY.with(|c| c.clone());
        let cache = OwningHandle::new_with_fn(cache_arc, |x| unsafe { x.as_ref() }.unwrap().borrow_mut());
-        debug_assert_eq!(cache.num_entries(), 0);
+        debug_assert!(cache.is_empty());

-        StyleSharingCandidateCache {
+        StyleSharingCache {
            cache_typeless: cache,
            marker: PhantomData,
            dom_depth: 0,
        }
    }

-    /// Returns the number of entries in the cache.
-    pub fn num_entries(&self) -> usize {
-        self.cache().num_entries()
-    }
-
-    fn iter_mut(&mut self) -> LRUCacheMutIterator<StyleSharingCandidate<E>> {
-        self.cache_mut().iter_mut()
-    }
-
    /// Tries to insert an element in the style sharing cache.
    ///
    /// Fails if we know it should never be in the cache.
+    ///
+    /// NB: We pass a source for the validation data, rather than the data itself,
+    /// to avoid memmoving at each function call. See rust issue #42763.
    pub fn insert_if_possible(&mut self,
                              element: &E,
                              style: &ComputedValues,
-                              validation_data: ValidationData,
+                              validation_data_holder: &mut StyleSharingTarget<E>,
                              dom_depth: usize) {
        let parent = match element.traversal_parent() {
            Some(element) => element,
@ -547,20 +554,12 @@ impl<E: TElement> StyleSharingCandidateCache<E> {
            self.clear();
            self.dom_depth = dom_depth;
        }
-        self.cache_mut().insert(StyleSharingCandidate {
-            element: *element,
-            validation_data: validation_data,
-        });
-    }
-
-    /// Touch a given index in the style sharing candidate cache.
-    pub fn touch(&mut self, index: usize) {
-        self.cache_mut().touch(index);
+        self.cache_mut().insert(*element, validation_data_holder);
    }

    /// Clear the style sharing candidate cache.
    pub fn clear(&mut self) {
-        self.cache_mut().evict_all()
+        self.cache_mut().clear();
    }

    /// Attempts to share a style with another node.
@ -570,48 +569,33 @@ impl<E: TElement> StyleSharingCandidateCache<E> {
        selector_flags_map: &mut SelectorFlagsMap<E>,
        bloom_filter: &StyleBloom<E>,
        target: &mut StyleSharingTarget<E>,
-    ) -> StyleSharingResult {
+    ) -> Option<ElementStyles> {
        if shared_context.options.disable_style_sharing_cache {
            debug!("{:?} Cannot share style: style sharing cache disabled",
                   target.element);
-            return StyleSharingResult::CannotShare
+            return None;
        }

        if target.traversal_parent().is_none() {
            debug!("{:?} Cannot share style: element has no parent",
                   target.element);
-            return StyleSharingResult::CannotShare
+            return None;
        }

        if target.is_native_anonymous() {
            debug!("{:?} Cannot share style: NAC", target.element);
-            return StyleSharingResult::CannotShare;
+            return None;
        }

-        for (i, candidate) in self.iter_mut().enumerate() {
-            let sharing_result =
-                Self::test_candidate(
-                    target,
-                    candidate,
-                    &shared_context,
-                    bloom_filter,
-                    selector_flags_map
-                );
-
-            match sharing_result {
-                Ok(shared_styles) => {
-                    return StyleSharingResult::StyleWasShared(i, shared_styles)
-                }
-                Err(miss) => {
-                    debug!("Cache miss: {:?}", miss);
-                }
-            }
-        }
-
-        debug!("{:?} Cannot share style: {} cache entries", target.element,
-               self.cache().num_entries());
-
-        StyleSharingResult::CannotShare
+        self.cache_mut().lookup(|candidate| {
+            Self::test_candidate(
+                target,
+                candidate,
+                &shared_context,
+                bloom_filter,
+                selector_flags_map
+            )
+        })
    }

    fn test_candidate(
@ -620,13 +604,7 @@ impl<E: TElement> StyleSharingCandidateCache<E> {
        shared: &SharedStyleContext,
        bloom: &StyleBloom<E>,
        selector_flags_map: &mut SelectorFlagsMap<E>
-    ) -> Result<ElementStyles, CacheMiss> {
-        macro_rules! miss {
-            ($miss: ident) => {
-                return Err(CacheMiss::$miss);
-            }
-        }
-
+    ) -> bool {
        // Check that we have the same parent, or at least that the parents
        // share styles and permit sharing across their children. The latter
        // check allows us to share style between cousins if the parents
@ -635,37 +613,44 @@ impl<E: TElement> StyleSharingCandidateCache<E> {
        let candidate_parent = candidate.element.traversal_parent();
        if parent != candidate_parent &&
           !checks::can_share_style_across_parents(parent, candidate_parent) {
-            miss!(Parent)
+            trace!("Miss: Parent");
+            return false;
        }

        if target.is_native_anonymous() {
            debug_assert!(!candidate.element.is_native_anonymous(),
                          "Why inserting NAC into the cache?");
-            miss!(NativeAnonymousContent)
+            trace!("Miss: Native Anonymous Content");
+            return false;
        }

        if *target.get_local_name() != *candidate.element.get_local_name() {
-            miss!(LocalName)
+            trace!("Miss: Local Name");
+            return false;
        }

        if *target.get_namespace() != *candidate.element.get_namespace() {
-            miss!(Namespace)
+            trace!("Miss: Namespace");
+            return false;
        }

        if target.is_link() != candidate.element.is_link() {
-            miss!(Link)
+            trace!("Miss: Link");
+            return false;
        }

        if target.matches_user_and_author_rules() !=
            candidate.element.matches_user_and_author_rules() {
-            miss!(UserAndAuthorRules)
+            trace!("Miss: User and Author Rules");
+            return false;
        }

        // We do not ignore visited state here, because Gecko
        // needs to store extra bits on visited style contexts,
        // so these contexts cannot be shared
        if target.element.get_state() != candidate.get_state() {
-            miss!(State)
+            trace!("Miss: User and Author State");
+            return false;
        }

        let element_id = target.element.get_id();
@ -674,32 +659,38 @@ impl<E: TElement> StyleSharingCandidateCache<E> {
            // It's possible that there are no styles for either id.
            if checks::may_have_rules_for_ids(shared, element_id.as_ref(),
                                              candidate_id.as_ref()) {
-                miss!(IdAttr)
+                trace!("Miss: ID Attr");
+                return false;
            }
        }

        if !checks::have_same_style_attribute(target, candidate) {
-            miss!(StyleAttr)
+            trace!("Miss: Style Attr");
+            return false;
        }

        if !checks::have_same_class(target, candidate) {
-            miss!(Class)
+            trace!("Miss: Class");
+            return false;
        }

        if !checks::have_same_presentational_hints(target, candidate) {
-            miss!(PresHints)
+            trace!("Miss: Pres Hints");
+            return false;
        }

        if !checks::revalidate(target, candidate, shared, bloom,
                               selector_flags_map) {
-            miss!(Revalidation)
+            trace!("Miss: Revalidation");
+            return false;
        }

-        let data = candidate.element.borrow_data().unwrap();
-        debug_assert!(target.has_current_styles_for_traversal(&data, shared.traversal_flags));
+        debug_assert!(target.has_current_styles_for_traversal(
+            &candidate.element.borrow_data().unwrap(),
+            shared.traversal_flags)
+        );
+        debug!("Sharing allowed between {:?} and {:?}", target.element, candidate.element);

-        debug!("Sharing style between {:?} and {:?}",
-               target.element, candidate.element);
-        Ok(data.styles.clone())
+        true
    }
 }
--- a/servo/components/style/traversal.rs
+++ b/servo/components/style/traversal.rs
@ -624,7 +624,6 @@ where
    E: TElement,
 {
    use data::RestyleKind::*;
-    use sharing::StyleSharingResult::*;

    context.thread_local.statistics.elements_styled += 1;
    let kind = data.restyle_kind(context.shared);
@ -656,12 +655,11 @@ where
            // Now that our bloom filter is set up, try the style sharing
            // cache.
            match target.share_style_if_possible(context) {
-                StyleWasShared(index, styles) => {
+                Some(styles) => {
                    context.thread_local.statistics.styles_shared += 1;
-                    context.thread_local.style_sharing_candidate_cache.touch(index);
                    styles
                }
-                CannotShare => {
+                None => {
                    context.thread_local.statistics.elements_matched += 1;
                    // Perform the matching and cascading.
                    let new_styles = {
@ -677,11 +675,11 @@ where
                    };

                    context.thread_local
-                        .style_sharing_candidate_cache
+                        .sharing_cache
                        .insert_if_possible(
                            &element,
                            new_styles.primary(),
-                            target.take_validation_data(),
+                            &mut target,
                            context.thread_local.bloom_filter.matching_depth(),
                        );

--- a/servo/tests/unit/stylo/size_of.rs
+++ b/servo/tests/unit/stylo/size_of.rs
@ -31,6 +31,9 @@ fn size_of_selectors_dummy_types() {
 // selectors (with the inline hashes) with as few cache misses as possible.
 size_of_test!(test_size_of_rule, style::stylist::Rule, 32);

+// Large pages generate tens of thousands of ComputedValues.
+size_of_test!(test_size_of_cv, ComputedValues, 272);
+
 size_of_test!(test_size_of_option_arc_cv, Option<Arc<ComputedValues>>, 8);
 size_of_test!(test_size_of_option_rule_node, Option<StrongRuleNode>, 8);

--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@ -11767,7 +11767,7 @@
  },
  "READER_MODE_PARSE_RESULT" : {
    "record_in_processes": ["main", "content"],
-    "expires_in_version": "58",
+    "expires_in_version": "never",
    "alert_emails": ["firefox-dev@mozilla.org", "gijs@mozilla.com"],
    "kind": "enumerated",
    "n_values": 5,
@ -11775,7 +11775,7 @@
  },
  "READER_MODE_DOWNLOAD_RESULT" : {
    "record_in_processes": ["main", "content"],
-    "expires_in_version": "58",
+    "expires_in_version": "never",
    "alert_emails": ["firefox-dev@mozilla.org", "gijs@mozilla.com"],
    "kind": "enumerated",
    "n_values": 5,
--- a/tools/coverity/model.cpp
+++ b/tools/coverity/model.cpp
@ -54,6 +54,14 @@ MOZ_ReportCrash(const char* aStr, const char* aFilename, int aLine)

 #define NS_RUNTIMEABORT(msg) __coverity_panic__()

+// Kills Structurally dead code (UNREACHABLE)
+#define NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_BEGIN(_class)                   \
+  NS_IMETHODIMP_(bool)                                                         \
+  NS_CYCLE_COLLECTION_CLASSNAME(_class)::CanSkipThisReal(void* p)              \
+  {                                                                            \
+    __coverity_panic__();                                                      \
+    _class* tmp = DowncastCCParticipant<_class>(p);
+
 int
 GET_JUMP_OFFSET(jsbytecode* pc)
 {