Invalidate scrolling contents on scrolling contents layer only

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

Index: third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
index 46f51bb1e039bc6de704030e6d337f9ff203abff..89853b76a500a085f4731da7d0e5171cf42c4955 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
@@ -1376,6 +1376,7 @@ enum ApplyToGraphicsLayersModeFlags {
     ApplyToMaskLayers = (1 << 4),
     ApplyToContentLayers = (1 << 5),
     ApplyToChildContainingLayers = (1 << 6), // layers between m_graphicsLayer and children
+    ApplyToScrollingContentsLayer = (1 << 7),
     ApplyToAllGraphicsLayers = (ApplyToSquashingLayer | ApplyToScrollbarLayers | ApplyToBackgroundLayer | ApplyToMaskLayers | ApplyToLayersAffectedByPreserve3D | ApplyToContentLayers)
 };
 typedef unsigned ApplyToGraphicsLayersMode;
@@ -1395,7 +1396,7 @@ static void ApplyToGraphicsLayers(const CompositedLayerMapping* mapping, const F
         f(mapping->scrollingLayer());
     if (((mode & ApplyToLayersAffectedByPreserve3D) || (mode & ApplyToChildContainingLayers)) && mapping->scrollingBlockSelectionLayer())
         f(mapping->scrollingBlockSelectionLayer());
-    if (((mode & ApplyToLayersAffectedByPreserve3D) || (mode & ApplyToContentLayers) || (mode & ApplyToChildContainingLayers)) && mapping->scrollingContentsLayer())
+    if (((mode & ApplyToLayersAffectedByPreserve3D) || (mode & ApplyToContentLayers) || (mode & ApplyToChildContainingLayers) || (mode & ApplyToScrollingContentsLayer)) && mapping->scrollingContentsLayer())
         f(mapping->scrollingContentsLayer());
     if (((mode & ApplyToLayersAffectedByPreserve3D) || (mode & ApplyToContentLayers)) && mapping->foregroundLayer())
         f(mapping->foregroundLayer());
@@ -2026,8 +2027,6 @@ struct SetContentsNeedsDisplayInRectFunctor {
 void CompositedLayerMapping::setContentsNeedDisplayInRect(const LayoutRect& r, PaintInvalidationReason invalidationReason)
 {
     ASSERT(!RuntimeEnabledFeatures::slimmingPaintSynchronizedPaintingEnabled());
-    // FIXME: need to split out paint invalidations for the background.
-    // FIXME: need to distinguish invalidations for different layers (e.g. the main layer and scrolling layer). crbug.com/416535.
     SetContentsNeedsDisplayInRectFunctor functor = {
         enclosingIntRect(LayoutRect(r.location() + m_owningLayer.subpixelAccumulation(), r.size())),
         invalidationReason
@@ -2037,13 +2036,18 @@ void CompositedLayerMapping::setContentsNeedDisplayInRect(const LayoutRect& r, P
 
 void CompositedLayerMapping::invalidateDisplayItemClient(const DisplayItemClientWrapper& displayItemClient, PaintInvalidationReason paintInvalidationReason, const LayoutRect& previousPaintInvalidationRect, const LayoutRect& newPaintInvalidationRect)
 {
-    // FIXME: need to split out paint invalidations for the background.
-    // FIXME: need to distinguish invalidations for different layers (e.g. the main layer and scrolling layer). crbug.com/416535.
     ApplyToGraphicsLayers(this, [&displayItemClient, paintInvalidationReason, previousPaintInvalidationRect, newPaintInvalidationRect](GraphicsLayer* layer) {
         layer->invalidateDisplayItemClient(displayItemClient, paintInvalidationReason, enclosingIntRect(previousPaintInvalidationRect), enclosingIntRect(newPaintInvalidationRect));
     }, ApplyToContentLayers);
 }
 
+void CompositedLayerMapping::invalidateDisplayItemClientOnScrollingContentsLayer(const DisplayItemClientWrapper& displayItemClient, PaintInvalidationReason paintInvalidationReason, const LayoutRect& previousPaintInvalidationRect, const LayoutRect& newPaintInvalidationRect)
+{
+    ApplyToGraphicsLayers(this, [&displayItemClient, paintInvalidationReason, previousPaintInvalidationRect, newPaintInvalidationRect](GraphicsLayer* layer) {
+        layer->invalidateDisplayItemClient(displayItemClient, paintInvalidationReason, enclosingIntRect(previousPaintInvalidationRect), enclosingIntRect(newPaintInvalidationRect));
+    }, ApplyToScrollingContentsLayer);
+}
+
 const GraphicsLayerPaintInfo* CompositedLayerMapping::containingSquashedLayer(const LayoutObject* layoutObject, const Vector<GraphicsLayerPaintInfo>& layers, unsigned maxSquashedLayerIndex)
 {
     for (size_t i = 0; i < layers.size() && i < maxSquashedLayerIndex; ++i) {