mix-blend-mode implementation for accelerated layers - blink part

Source/core/rendering/CompositedLayerMapping.cpp

Index: Source/core/rendering/CompositedLayerMapping.cpp
diff --git a/Source/core/rendering/CompositedLayerMapping.cpp b/Source/core/rendering/CompositedLayerMapping.cpp
index 536a35118a5c0041305fe0dc71df3395a7ec08f9..9d3d4f54b2a777a443e60211bd90ca9f67f7552b 100644
--- a/Source/core/rendering/CompositedLayerMapping.cpp
+++ b/Source/core/rendering/CompositedLayerMapping.cpp
@@ -213,8 +213,10 @@ void CompositedLayerMapping::createPrimaryGraphicsLayer()
     updateTransform(renderer()->style());
     updateFilters(renderer()->style());
 
-    if (RuntimeEnabledFeatures::cssCompositingEnabled())
+    if (RuntimeEnabledFeatures::cssCompositingEnabled()) {
         updateLayerBlendMode(renderer()->style());
+        updateIsRootForIsolatedGroup();
+    }
 }
 
 void CompositedLayerMapping::destroyGraphicsLayers()
@@ -271,8 +273,19 @@ void CompositedLayerMapping::updateFilters(const RenderStyle* style)
     }
 }
 
-void CompositedLayerMapping::updateLayerBlendMode(const RenderStyle*)
+void CompositedLayerMapping::updateLayerBlendMode(const RenderStyle* style)
+{
+    setBlendMode(style->blendMode());
+}
+
+void CompositedLayerMapping::updateIsRootForIsolatedGroup()
 {
+    bool isolate = m_owningLayer->shouldIsolateCompositedDescendants();
+
+    // non stacking context layers should never isolate
+    ASSERT(m_owningLayer->stackingNode()->isStackingContext() || !isolate);
+
+    m_graphicsLayer->setIsRootForIsolatedGroup(isolate);
 }
 
 void CompositedLayerMapping::updateContentsOpaque()
@@ -532,9 +545,6 @@ void CompositedLayerMapping::updateGraphicsLayerGeometry()
         : !renderer()->animation().isRunningAcceleratedAnimationOnRenderer(renderer(), CSSPropertyOpacity))
         updateOpacity(renderer()->style());
 
-    if (RuntimeEnabledFeatures::cssCompositingEnabled())
-        updateLayerBlendMode(renderer()->style());
-
     bool isSimpleContainer = isSimpleContainerCompositingLayer();
 
     m_owningLayer->updateDescendantDependentFlags();
@@ -782,6 +792,11 @@ void CompositedLayerMapping::updateGraphicsLayerGeometry()
     // since it depends on whether compAncestor draws content, which gets updated later.
     updateRequiresOwnBackingStoreForAncestorReasons(compAncestor);
 
+    if (RuntimeEnabledFeatures::cssCompositingEnabled()) {
+        updateLayerBlendMode(style);
+        updateIsRootForIsolatedGroup();
+    }
+
     updateContentsRect(isSimpleContainer);
     updateBackgroundColor(isSimpleContainer);
     updateDrawsContent(isSimpleContainer);
@@ -1590,8 +1605,15 @@ void CompositedLayerMapping::paintsIntoCompositedAncestorChanged()
     compositor()->repaintInCompositedAncestor(m_owningLayer, compositedBounds());
 }
 
-void CompositedLayerMapping::setBlendMode(BlendMode)
+void CompositedLayerMapping::setBlendMode(BlendMode blendMode)
 {
+    if (m_ancestorClippingLayer) {
+        ASSERT(childForSuperlayers() == m_ancestorClippingLayer.get());
+        m_graphicsLayer->setBlendMode(BlendModeNormal);
+    } else {
+        ASSERT(childForSuperlayers() == m_graphicsLayer.get());
+    }
+    childForSuperlayers()->setBlendMode(blendMode);
 }
 
 void CompositedLayerMapping::setContentsNeedDisplay()