Bug 1449756 - Make DisplayPort suppression PresShell specific and not process global. r=kats

Originally, DisplayPort suppression was a process-global static. This change makes it possible
to control DisplayPort suppression on a per-PresShell basis.

Differential Revision: https://phabricator.services.mozilla.com/D1759

dom/base/nsDOMWindowUtils.cpp

@@ -4178,7 +4178,7 @@ NS_IMETHODIMP
 nsDOMWindowUtils::RespectDisplayPortSuppression(bool aEnabled)
 {
   nsCOMPtr<nsIPresShell> shell(GetPresShell());
-  APZCCallbackHelper::RespectDisplayPortSuppression(aEnabled, shell);
+  shell->RespectDisplayportSuppression(aEnabled);
   return NS_OK;
 }
 

dom/ipc/TabChild.cpp

@@ -402,7 +402,6 @@ TabChild::TabChild(nsIContentChild* aManager,
   , mManager(aManager)
   , mChromeFlags(aChromeFlags)
   , mMaxTouchPoints(0)
-  , mActiveSuppressDisplayport(0)
   , mLayersId{0}
   , mBeforeUnloadListeners(0)
   , mDidFakeShow(false)
@@ -1343,14 +1342,9 @@ TabChild::UpdateFrame(const FrameMetrics& aFrameMetrics)
 mozilla::ipc::IPCResult
 TabChild::RecvSuppressDisplayport(const bool& aEnabled)
 {
-  if (aEnabled) {
+  if (nsCOMPtr<nsIPresShell> shell = GetPresShell()) {
-    mActiveSuppressDisplayport++;
+    shell->SuppressDisplayport(aEnabled);
-  } else {
-    mActiveSuppressDisplayport--;
   }
-
-  MOZ_ASSERT(mActiveSuppressDisplayport >= 0);
-  APZCCallbackHelper::SuppressDisplayport(aEnabled, GetPresShell());
   return IPC_OK();
 }
 
@@ -2503,11 +2497,6 @@ TabChild::RecvDestroy()
       child->Destroy();
   }
 
-  while (mActiveSuppressDisplayport > 0) {
-    APZCCallbackHelper::SuppressDisplayport(false, nullptr);
-    mActiveSuppressDisplayport--;
-  }
-
   if (mTabChildGlobal) {
     // Message handlers are called from the event loop, so it better be safe to
     // run script.
@@ -2665,7 +2654,7 @@ TabChild::RecvRenderLayers(const bool& aEnabled, const bool& aForceRepaint, cons
       // we get back to the event loop again. We suppress the display port so that
       // we only paint what's visible. This ensures that the tab we're switching
       // to paints as quickly as possible.
-      APZCCallbackHelper::SuppressDisplayport(true, presShell);
+      presShell->SuppressDisplayport(true);
       if (nsContentUtils::IsSafeToRunScript()) {
         WebWidget()->PaintNowIfNeeded();
       } else {
@@ -2675,7 +2664,7 @@ TabChild::RecvRenderLayers(const bool& aEnabled, const bool& aForceRepaint, cons
                            nsIPresShell::PAINT_LAYERS);
         }
       }
-      APZCCallbackHelper::SuppressDisplayport(false, presShell);
+      presShell->SuppressDisplayport(false);
     }
   } else {
     if (sVisibleTabs) {

dom/ipc/TabChild.h

@@ -828,7 +828,6 @@ private:
   RefPtr<nsIContentChild> mManager;
   uint32_t mChromeFlags;
   uint32_t mMaxTouchPoints;
-  int32_t mActiveSuppressDisplayport;
   layers::LayersId mLayersId;
   int64_t mBeforeUnloadListeners;
   CSSRect mUnscaledOuterRect;

gfx/layers/apz/util/APZCCallbackHelper.cpp

@@ -884,48 +884,6 @@ APZCCallbackHelper::NotifyFlushComplete(nsIPresShell* aShell)
   observerService->NotifyObservers(nullptr, "apz-repaints-flushed", nullptr);
 }
 
-static int32_t sActiveSuppressDisplayport = 0;
-static bool sDisplayPortSuppressionRespected = true;
-
-void
-APZCCallbackHelper::SuppressDisplayport(const bool& aEnabled,
-                                        const nsCOMPtr<nsIPresShell>& aShell)
-{
-  if (aEnabled) {
-    sActiveSuppressDisplayport++;
-  } else {
-    bool isSuppressed = IsDisplayportSuppressed();
-    sActiveSuppressDisplayport--;
-    if (isSuppressed && !IsDisplayportSuppressed() &&
-        aShell && aShell->GetRootFrame()) {
-      // We unsuppressed the displayport, trigger a paint
-      aShell->GetRootFrame()->SchedulePaint();
-    }
-  }
-
-  MOZ_ASSERT(sActiveSuppressDisplayport >= 0);
-}
-
-void
-APZCCallbackHelper::RespectDisplayPortSuppression(bool aEnabled,
-                                                  const nsCOMPtr<nsIPresShell>& aShell)
-{
-  bool isSuppressed = IsDisplayportSuppressed();
-  sDisplayPortSuppressionRespected = aEnabled;
-  if (isSuppressed && !IsDisplayportSuppressed() &&
-      aShell && aShell->GetRootFrame()) {
-    // We unsuppressed the displayport, trigger a paint
-    aShell->GetRootFrame()->SchedulePaint();
-  }
-}
-
-bool
-APZCCallbackHelper::IsDisplayportSuppressed()
-{
-  return sDisplayPortSuppressionRespected
-      && sActiveSuppressDisplayport > 0;
-}
-
 /* static */ bool
 APZCCallbackHelper::IsScrollInProgress(nsIScrollableFrame* aFrame)
 {

gfx/layers/apz/util/APZCCallbackHelper.h

@@ -194,27 +194,6 @@ public:
 
     static void CancelAutoscroll(const FrameMetrics::ViewID& aScrollId);
 
-    /* Temporarily ignore the Displayport for better paint performance. If at
-     * all possible, pass in a presShell if you have one at the call site, we
-     * use it to trigger a repaint once suppression is disabled. Without that
-     * the displayport may get left at the suppressed size for an extended
-     * period of time and result in unnecessary checkerboarding (see bug
-     * 1255054). */
-    static void SuppressDisplayport(const bool& aEnabled,
-                                    const nsCOMPtr<nsIPresShell>& aShell);
-
-    /* Whether or not displayport suppression should be turned on. Note that
-     * this only affects the return value of |IsDisplayportSuppressed()|, and
-     * doesn't change the value of the internal counter. As with
-     * SuppressDisplayport, this function should be passed a presShell to trigger
-     * a repaint if suppression is being turned off.
-     */
-    static void RespectDisplayPortSuppression(bool aEnabled,
-                                              const nsCOMPtr<nsIPresShell>& aShell);
-
-    /* Whether or not the displayport is currently suppressed. */
-    static bool IsDisplayportSuppressed();
-
     static void
     AdjustDisplayPortForScrollDelta(mozilla::layers::FrameMetrics& aFrameMetrics,
                                     const CSSPoint& aActualScrollOffset);

layout/base/PresShell.cpp

@@ -809,6 +809,7 @@ PresShell::PresShell()
   , mLastCallbackEventRequest(nullptr)
   , mLastReflowStart(0.0)
   , mLastAnchorScrollPositionY(0)
+  , mActiveSuppressDisplayport(0)
   , mAPZFocusSequenceNumber(0)
   , mDocumentLoading(false)
   , mIgnoreFrameDestruction(false)
@@ -8555,6 +8556,47 @@ PresShell::IsVisible()
   return frame->IsVisibleConsideringAncestors(nsIFrame::VISIBILITY_CROSS_CHROME_CONTENT_BOUNDARY);
 }
 
+void
+PresShell::SuppressDisplayport(bool aEnabled)
+{
+  if (aEnabled) {
+    mActiveSuppressDisplayport++;
+  } else {
+    bool isSuppressed = IsDisplayportSuppressed();
+    mActiveSuppressDisplayport--;
+    if (isSuppressed && !IsDisplayportSuppressed()) {
+      // We unsuppressed the displayport, trigger a paint
+      if (nsIFrame* rootFrame = mFrameConstructor->GetRootFrame()) {
+        rootFrame->SchedulePaint();
+      }
+    }
+  }
+
+  MOZ_ASSERT(mActiveSuppressDisplayport >= 0);
+}
+
+static bool sDisplayPortSuppressionRespected = true;
+
+void
+PresShell::RespectDisplayportSuppression(bool aEnabled)
+{
+  bool isSuppressed = IsDisplayportSuppressed();
+  sDisplayPortSuppressionRespected = aEnabled;
+  if (isSuppressed && !IsDisplayportSuppressed()) {
+    // We unsuppressed the displayport, trigger a paint
+    if (nsIFrame* rootFrame = mFrameConstructor->GetRootFrame()) {
+      rootFrame->SchedulePaint();
+    }
+  }
+}
+
+bool
+PresShell::IsDisplayportSuppressed()
+{
+  return sDisplayPortSuppressionRespected &&
+         mActiveSuppressDisplayport > 0;
+}
+
 nsresult
 PresShell::GetAgentStyleSheets(nsTArray<RefPtr<StyleSheet>>& aSheets)
 {

layout/base/PresShell.h

@@ -245,6 +245,9 @@ public:
   void ScheduleViewManagerFlush(PaintType aType = PAINT_DEFAULT) override;
   void ClearMouseCaptureOnView(nsView* aView) override;
   bool IsVisible() override;
+  void SuppressDisplayport(bool aEnabled) override;
+  void RespectDisplayportSuppression(bool aEnabled) override;
+  bool IsDisplayportSuppressed() override;
 
   already_AddRefed<AccessibleCaretEventHub> GetAccessibleCaretEventHub() const override;
 
@@ -830,6 +833,8 @@ private:
   // when target of pointer event was deleted during executing user handlers.
   nsCOMPtr<nsIContent> mPointerEventTarget;
 
+  int32_t mActiveSuppressDisplayport;
+
   // The focus sequence number of the last processed input event
   uint64_t mAPZFocusSequenceNumber;
   // The focus information needed for async keyboard scrolling

layout/base/nsIPresShell.h

@@ -1505,6 +1505,22 @@ public:
   virtual bool IsVisible() = 0;
   void DispatchSynthMouseMove(mozilla::WidgetGUIEvent* aEvent);
 
+  /* Temporarily ignore the Displayport for better paint performance. We
+   * trigger a repaint once suppression is disabled. Without that
+   * the displayport may get left at the suppressed size for an extended
+   * period of time and result in unnecessary checkerboarding (see bug
+   * 1255054). */
+  virtual void SuppressDisplayport(bool aEnabled) = 0;
+
+  /* Whether or not displayport suppression should be turned on. Note that
+   * this only affects the return value of |IsDisplayportSuppressed()|, and
+   * doesn't change the value of the internal counter.
+   */
+  virtual void RespectDisplayportSuppression(bool aEnabled) = 0;
+
+  /* Whether or not the displayport is currently suppressed. */
+  virtual bool IsDisplayportSuppressed() = 0;
+
   virtual void AddSizeOfIncludingThis(nsWindowSizes& aWindowSizes) const = 0;
 
   /**

layout/base/nsLayoutUtils.cpp

@@ -877,7 +877,10 @@ GetDisplayPortFromMarginsData(nsIContent* aContent,
   //   the choosing of the resolution to display-list building time.
   ScreenSize alignment;
 
-  if (APZCCallbackHelper::IsDisplayportSuppressed()) {
+  nsIPresShell* presShell = presContext->PresShell();
+  MOZ_ASSERT(presShell);
+
+  if (presShell->IsDisplayportSuppressed()) {
     alignment = ScreenSize(1, 1);
   } else if (gfxPrefs::LayersTilesEnabled()) {
     // Don't align to tiles if they are too large, because we could expand
@@ -1098,10 +1101,21 @@ GetDisplayPortImpl(nsIContent* aContent, nsRect* aResult, float aMultiplier,
     return true;
   }
 
+  bool isDisplayportSuppressed = false;
+
+  nsIFrame* frame = aContent->GetPrimaryFrame();
+  if (frame) {
+    nsPresContext* presContext = frame->PresContext();
+    MOZ_ASSERT(presContext);
+    nsIPresShell* presShell = presContext->PresShell();
+    MOZ_ASSERT(presShell);
+    isDisplayportSuppressed = presShell->IsDisplayportSuppressed();
+  }
+
   nsRect result;
   if (rectData) {
     result = GetDisplayPortFromRectData(aContent, rectData, aMultiplier);
-  } else if (APZCCallbackHelper::IsDisplayportSuppressed() ||
+  } else if (isDisplayportSuppressed ||
       nsLayoutUtils::ShouldDisableApzForElement(aContent)) {
     DisplayPortMarginsPropertyData noMargins(ScreenMargin(), 1);
     result = GetDisplayPortFromMarginsData(aContent, &noMargins, aMultiplier);

layout/generic/nsGfxScrollFrame.cpp

@@ -1913,7 +1913,9 @@ public:
     }
 
     mCallee = aCallee;
-    APZCCallbackHelper::SuppressDisplayport(true, mCallee->mOuter->PresShell());
+    if (nsIPresShell* shell = mCallee->mOuter->PresShell()) {
+      shell->SuppressDisplayport(true);
+    }
     return true;
   }
 
@@ -1938,7 +1940,9 @@ private:
   void RemoveObserver() {
     if (mCallee) {
       RefreshDriver(mCallee)->RemoveRefreshObserver(this, FlushType::Style);
-      APZCCallbackHelper::SuppressDisplayport(false, mCallee->mOuter->PresShell());
+      if (nsIPresShell* shell = mCallee->mOuter->PresShell()) {
+        shell->SuppressDisplayport(false);
+      }
     }
   }
 };

layout/xul/nsSliderFrame.cpp

@@ -99,9 +99,9 @@ nsSliderFrame::nsSliderFrame(ComputedStyle* aStyle)
 nsSliderFrame::~nsSliderFrame()
 {
   if (mSuppressionActive) {
-    APZCCallbackHelper::SuppressDisplayport(false, PresContext() ?
+    if (nsIPresShell* shell = PresShell()) {
-                                                   PresShell() :
+      shell->SuppressDisplayport(false);
-                                                   nullptr);
+    }
   }
 }
 
@@ -1618,8 +1618,9 @@ void
 nsSliderFrame::SuppressDisplayport()
 {
   if (!mSuppressionActive) {
-    MOZ_ASSERT(PresShell());
+    nsIPresShell* shell = PresShell();
-    APZCCallbackHelper::SuppressDisplayport(true, PresShell());
+    MOZ_ASSERT(shell);
+    shell->SuppressDisplayport(true);
     mSuppressionActive = true;
   }
 }
@@ -1628,8 +1629,9 @@ void
 nsSliderFrame::UnsuppressDisplayport()
 {
   if (mSuppressionActive) {
-    MOZ_ASSERT(PresShell());
+    nsIPresShell* shell = PresShell();
-    APZCCallbackHelper::SuppressDisplayport(false, PresShell());
+    MOZ_ASSERT(shell);
+    shell->SuppressDisplayport(false);
     mSuppressionActive = false;
   }
 }