Bug 539356 - Part 19 - Only repaint retained layers after the previous repainted has been drawn to the window. r=roc

layout/base/nsRefreshDriver.cpp

@@ -415,7 +415,8 @@ nsRefreshDriver::Notify(nsITimer *aTimer)
     printf("Starting ProcessPendingUpdates\n");
 #endif
     mViewManagerFlushIsPending = false;
-    mPresContext->GetPresShell()->GetViewManager()->ProcessPendingUpdates();
+    bool skippedFlush = mPresContext->GetPresShell()->GetViewManager()->ProcessPendingUpdates();
+    mViewManagerFlushIsPending |= skippedFlush;
 #ifdef DEBUG_INVALIDATIONS
     printf("Ending ProcessPendingUpdates\n");
 #endif

view/public/nsIViewManager.h

@@ -296,8 +296,11 @@ public:
   /**
    * Flush the accumulated dirty region to the widget and update widget
    * geometry.
+   *
+   * @param True if a paint was skipped due to throttling and this
+   * should be called again after a delay.
    */
-  virtual void ProcessPendingUpdates()=0;
+  virtual bool ProcessPendingUpdates()=0;
 
   /**
    * Just update widget geometry without flushing the dirty region

view/src/nsView.cpp

@@ -176,6 +176,8 @@ nsView::nsView(nsViewManager* aViewManager, nsViewVisibility aVisibility)
   mDirtyRegion = nsnull;
   mDeletionObserver = nsnull;
   mWidgetIsTopLevel = false;
+  mPendingRefresh = false;
+  mSkippedPaints = 0;
 }
 
 void nsView::DropMouseGrabbing()

view/src/nsView.h

@@ -162,6 +162,13 @@ public:
   nsPoint GetOffsetTo(const nsView* aOther, const PRInt32 aAPD) const;
   nsIWidget* GetNearestWidget(nsPoint* aOffset, const PRInt32 aAPD) const;
 
+  void SetPendingRefresh(bool aPending) { mPendingRefresh = aPending; }
+  bool PendingRefresh() { return mPendingRefresh; }
+
+  void SkippedPaint() { mSkippedPaints++; }
+  void ClearSkippedPaints() { mSkippedPaints = 0; }
+  PRUint32 SkippedPaints() { return mSkippedPaints; }
+
 protected:
   // Do the actual work of ResetWidgetBounds, unconditionally.  Don't
   // call this method if we have no widget.
@@ -169,6 +176,15 @@ protected:
 
   nsRegion*    mDirtyRegion;
 
+  // True if the view has invalidate scheduled with the widget
+  // and is waiting for nsViewManager::Refresh to be called.
+  bool mPendingRefresh;
+
+  // True if a paint event was skipped while mPendingRefresh was
+  // true, and a new one should be scheduled once we get
+  // nsViewManager::Refresh called.
+  PRUint32 mSkippedPaints;
+
 private:
   void InitializeWindow(bool aEnableDragDrop, bool aResetVisibility);
 };

view/src/nsViewManager.cpp

@@ -303,6 +303,11 @@ void nsViewManager::Refresh(nsView *aView, const nsIntRegion& aRegion,
                             bool aWillSendDidPaint)
 {
   NS_ASSERTION(aView->GetViewManager() == this, "wrong view manager");
+  aView->SetPendingRefresh(false);
+  if (aView->SkippedPaints()) {
+    RootViewManager()->GetPresShell()->ScheduleViewManagerFlush(true);
+    aView->ClearSkippedPaints();
+  }
 
   // damageRegion is the damaged area, in twips, relative to the view origin
   nsRegion damageRegion = aRegion.ToAppUnits(AppUnitsPerDevPixel());
@@ -354,14 +359,14 @@ void nsViewManager::Refresh(nsView *aView, const nsIntRegion& aRegion,
   }
 }
 
-void nsViewManager::ProcessPendingUpdatesForView(nsView* aView,
+bool nsViewManager::ProcessPendingUpdatesForView(nsView* aView,
                                                  bool aFlushDirtyRegion)
 {
   NS_ASSERTION(IsRootVM(), "Updates will be missed");
 
   // Protect against a null-view.
   if (!aView) {
-    return;
+    return false;
   }
 
   if (aView->HasWidget()) {
@@ -369,9 +374,10 @@ void nsViewManager::ProcessPendingUpdatesForView(nsView* aView,
   }
 
   // process pending updates in child view.
+  bool skipped = false;
   for (nsView* childView = aView->GetFirstChild(); childView;
        childView = childView->GetNextSibling()) {
-    ProcessPendingUpdatesForView(childView, aFlushDirtyRegion);
+    skipped |= ProcessPendingUpdatesForView(childView, aFlushDirtyRegion);
   }
 
   // Push out updates after we've processed the children; ensures that
@@ -379,18 +385,28 @@ void nsViewManager::ProcessPendingUpdatesForView(nsView* aView,
   if (aFlushDirtyRegion) {
     nsIWidget *widget = aView->GetWidget();
     if (widget && widget->NeedsPaint()) {
-      widget->SetNeedsPaint(false);
+      if (aView->PendingRefresh() && aView->SkippedPaints() < 5) {
+        aView->SkippedPaint();
+        skipped = true;
+      } else {
+        aView->ClearSkippedPaints();
+        aView->SetPendingRefresh(false);
+        widget->SetNeedsPaint(false);
+        SetPainting(true);
 #ifdef DEBUG_INVALIDATIONS
-      printf("---- PAINT START ----PresShell(%p), nsView(%p), nsIWidget(%p)\n", mPresShell, aView, widget);
+        printf("---- PAINT START ----PresShell(%p), nsView(%p), nsIWidget(%p)\n", mPresShell, aView, widget);
 #endif
-      nsAutoScriptBlocker scriptBlocker;
-      mPresShell->Paint(aView, nsRegion(), nsIPresShell::PaintType_NoComposite, false);
+        nsAutoScriptBlocker scriptBlocker;
+        mPresShell->Paint(aView, nsRegion(), nsIPresShell::PaintType_NoComposite, false);
 #ifdef DEBUG_INVALIDATIONS
-      printf("---- PAINT END ----\n");
+        printf("---- PAINT END ----\n");
 #endif
+        SetPainting(false);
+      }
     }
     FlushDirtyRegionToWidget(aView);
   }
+  return skipped;
 }
 
 void nsViewManager::FlushDirtyRegionToWidget(nsView* aView)
@@ -433,7 +449,7 @@ nsViewManager::PostPendingUpdate()
 {
   nsViewManager* rootVM = RootViewManager();
   rootVM->mHasPendingWidgetGeometryChanges = true;
-  if (rootVM->mPresShell) {
+  if (rootVM->mPresShell && !rootVM->IsPainting()) {
     rootVM->mPresShell->ScheduleViewManagerFlush(nsIFrame::PAINT_COMPOSITE_ONLY);
   }
 }
@@ -516,6 +532,7 @@ nsViewManager::InvalidateWidgetArea(nsView *aWidgetView,
   leftOver.Sub(aDamagedRegion, children);
 
   if (!leftOver.IsEmpty()) {
+    aWidgetView->SetPendingRefresh(true);
     const nsRect* r;
     for (nsRegionRectIterator iter(leftOver); (r = iter.Next());) {
       nsIntRect bounds = ViewToWidget(aWidgetView, *r);
@@ -1302,16 +1319,15 @@ nsViewManager::IsPainting(bool& aIsPainting)
   return NS_OK;
 }
 
-void
+bool
 nsViewManager::ProcessPendingUpdates()
 {
   if (!IsRootVM()) {
-    RootViewManager()->ProcessPendingUpdates();
-    return;
+    return RootViewManager()->ProcessPendingUpdates();
   }
 
   mPresShell->GetPresContext()->RefreshDriver()->RevokeViewManagerFlush();
-  ProcessPendingUpdatesForView(mRootView, true);
+  return ProcessPendingUpdatesForView(mRootView, true);
 }
 
 void

view/src/nsViewManager.h

@@ -105,7 +105,7 @@ public:
   /* Update the cached RootViewManager pointer on this view manager. */
   void InvalidateHierarchy();
 
-  virtual void ProcessPendingUpdates();
+  virtual bool ProcessPendingUpdates();
   virtual void UpdateWidgetGeometry();
 
 protected:
@@ -114,7 +114,10 @@ protected:
 private:
 
   void FlushPendingInvalidates();
-  void ProcessPendingUpdatesForView(nsView *aView,
+  /* Returns true if we skipped painting a view and we should try
+   * again later.
+   */
+  bool ProcessPendingUpdatesForView(nsView *aView,
                                     bool aFlushDirtyRegion = true);
   void FlushDirtyRegionToWidget(nsView* aView);
   /**