Repaint squashing content in cases where the entire frame is repainting.

In the process, inline RenderLayerRepainter::setBackingNeedsRepaint's one call site
and remove the method.

BUG=384520

Review URL: https://codereview.chromium.org/337793004

git-svn-id: svn://svn.chromium.org/blink/trunk@176150 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/core/rendering/RenderLayer.cpp

@@ -301,8 +301,13 @@ void RenderLayer::updateLayerPositionRecursive(UpdateLayerPositionsFlags flags)
     for (RenderLayer* child = firstChild(); child; child = child->nextSibling())
         child->updateLayerPositionRecursive(flags);
 
-    if ((flags & NeedsFullRepaintInBacking) && hasCompositedLayerMapping() && !compositedLayerMapping()->paintsIntoCompositedAncestor())
+    // FIXME: why isn't FrameView just calling RenderLayerCompositor::repaintCompositedLayers? Does it really impact
+    // performance?
+    if ((flags & NeedsFullRepaintInBacking) && hasCompositedLayerMapping() && !compositedLayerMapping()->paintsIntoCompositedAncestor()) {
         compositedLayerMapping()->setContentsNeedDisplay();
+        // This code is called when the FrameView wants to repaint the entire frame. This includes squashing content.
+        compositedLayerMapping()->setSquashingContentsNeedDisplay();
+    }
 }
 
 void RenderLayer::setAncestorChainHasSelfPaintingLayerDescendant()

third_party/WebKit/Source/core/rendering/RenderLayerRepainter.cpp

@@ -184,14 +184,6 @@ LayoutRect RenderLayerRepainter::repaintRectIncludingNonCompositingDescendants()
     return repaintRect;
 }
 
-void RenderLayerRepainter::setBackingNeedsRepaint()
-{
-    // There is only one call site, and that call site ensures that the compositing state is PaintsIntoOwnBacking.
-    ASSERT(m_renderer.compositingState() == PaintsIntoOwnBacking);
-
-    m_renderer.compositedLayerMapping()->setContentsNeedDisplay();
-}
-
 void RenderLayerRepainter::setBackingNeedsRepaintInRect(const LayoutRect& r)
 {
     // https://bugs.webkit.org/show_bug.cgi?id=61159 describes an unreproducible crash here,

third_party/WebKit/Source/core/rendering/RenderLayerRepainter.h

@@ -79,7 +79,6 @@ public:
 
     // Indicate that the layer contents need to be repainted. Only has an effect
     // if layer compositing is being used,
-    void setBackingNeedsRepaint();
     void setBackingNeedsRepaintInRect(const LayoutRect&); // r is in the coordinate space of the layer's render object
 
     void setFilterBackendNeedsRepaintingInRect(const LayoutRect&);

third_party/WebKit/Source/core/rendering/compositing/CompositedLayerMapping.cpp

@@ -1869,6 +1869,11 @@ struct SetContentsNeedsDisplayFunctor {
     }
 };
 
+void CompositedLayerMapping::setSquashingContentsNeedDisplay()
+{
+    ApplyToGraphicsLayers(this, SetContentsNeedsDisplayFunctor(), ApplyToSquashingLayer);
+}
+
 void CompositedLayerMapping::setContentsNeedDisplay()
 {
     // FIXME: need to split out repaints for the background.

third_party/WebKit/Source/core/rendering/compositing/CompositedLayerMapping.h

@@ -143,6 +143,7 @@ public:
     // a backing store changed.
     bool updateRequiresOwnBackingStoreForIntrinsicReasons();
 
+    void setSquashingContentsNeedDisplay();
     void setContentsNeedDisplay();
     // r is in the coordinate space of the layer's render object
     void setContentsNeedDisplayInRect(const IntRect&);

third_party/WebKit/Source/core/rendering/compositing/RenderLayerCompositor.cpp

@@ -680,8 +680,12 @@ void RenderLayerCompositor::repaintCompositedLayers()
 void RenderLayerCompositor::recursiveRepaintLayer(RenderLayer* layer)
 {
     // FIXME: This method does not work correctly with transforms.
-    if (layer->compositingState() == PaintsIntoOwnBacking)
-        layer->repainter().setBackingNeedsRepaint();
+    if (layer->compositingState() == PaintsIntoOwnBacking) {
+        layer->compositedLayerMapping()->setContentsNeedDisplay();
+        // This function is called only when it is desired to repaint the entire compositing graphics layer tree.
+        // This includes squashing.
+        layer->compositedLayerMapping()->setSquashingContentsNeedDisplay();
+    }
 
     layer->stackingNode()->updateLayerListsIfNeeded();