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

Source/core/rendering/RenderLayerCompositor.cpp

Index: Source/core/rendering/RenderLayerCompositor.cpp
diff --git a/Source/core/rendering/RenderLayerCompositor.cpp b/Source/core/rendering/RenderLayerCompositor.cpp
index 09084ed814cd94e77220d8a4c2544b9a43907d86..cf6fe341df00e8f0e94ab9013b88b23f4e7b24d2 100644
--- a/Source/core/rendering/RenderLayerCompositor.cpp
+++ b/Source/core/rendering/RenderLayerCompositor.cpp
@@ -177,6 +177,7 @@ struct CompositingRecursionData {
     CompositingRecursionData(RenderLayer* compAncestor, bool testOverlap)
         : m_compositingAncestor(compAncestor)
         , m_subtreeIsCompositing(false)
+        , m_hasUnisolatedCompositedBlendingDescendant(false)
         , m_testingOverlap(testOverlap)
 #ifndef NDEBUG
         , m_depth(0)
@@ -187,6 +188,7 @@ struct CompositingRecursionData {
     CompositingRecursionData(const CompositingRecursionData& other)
         : m_compositingAncestor(other.m_compositingAncestor)
         , m_subtreeIsCompositing(other.m_subtreeIsCompositing)
+        , m_hasUnisolatedCompositedBlendingDescendant(other.m_hasUnisolatedCompositedBlendingDescendant)
         , m_testingOverlap(other.m_testingOverlap)
 #ifndef NDEBUG
         , m_depth(other.m_depth + 1)
@@ -196,6 +198,7 @@ struct CompositingRecursionData {
 
     RenderLayer* m_compositingAncestor;
     bool m_subtreeIsCompositing;
+    bool m_hasUnisolatedCompositedBlendingDescendant;
     bool m_testingOverlap;
 #ifndef NDEBUG
     int m_depth;
@@ -914,6 +917,13 @@ void RenderLayerCompositor::computeCompositingRequirements(RenderLayer* ancestor
     if (overlapMap && childRecursionData.m_compositingAncestor && !childRecursionData.m_compositingAncestor->isRootLayer())
         addToOverlapMap(*overlapMap, layer, absBounds, haveComputedBounds);
 
+    if (layer->stackingNode()->isStackingContext()) {
+        layer->setShouldIsolateCompositedDescendants(childRecursionData.m_hasUnisolatedCompositedBlendingDescendant);
+    } else {
+        layer->setShouldIsolateCompositedDescendants(false);
+        currentRecursionData.m_hasUnisolatedCompositedBlendingDescendant = childRecursionData.m_hasUnisolatedCompositedBlendingDescendant;
+    }
+
     // Now check for reasons to become composited that depend on the state of descendant layers.
     CompositingReasons subtreeCompositingReasons = subtreeReasonsForCompositing(layer->renderer(), childRecursionData.m_subtreeIsCompositing, anyDescendantHas3DTransform);
     reasonsToComposite |= subtreeCompositingReasons;
@@ -940,6 +950,9 @@ void RenderLayerCompositor::computeCompositingRequirements(RenderLayer* ancestor
     if (childRecursionData.m_subtreeIsCompositing)
         currentRecursionData.m_subtreeIsCompositing = true;
 
+    if (willBeComposited && layer->hasBlendMode())
+        currentRecursionData.m_hasUnisolatedCompositedBlendingDescendant = true;
+
     // Set the flag to say that this SC has compositing children.
     layer->setHasCompositingDescendant(childRecursionData.m_subtreeIsCompositing);
 
@@ -1746,6 +1759,11 @@ CompositingReasons RenderLayerCompositor::subtreeReasonsForCompositing(RenderObj
         if (layer->transform())
             subtreeReasons |= CompositingReasonTransformWithCompositedDescendants;
 
+        if (layer->shouldIsolateCompositedDescendants()) {
+            ASSERT(layer->stackingNode()->isStackingContext());
+            subtreeReasons |= CompositingReasonIsolateCompositedDescendants;
+        }
+
         // If the implementation of createsGroup changes, we need to be aware of that in this part of code.
         ASSERT((renderer->isTransparent() || renderer->hasMask() || renderer->hasFilter() || renderer->hasBlendMode()) == renderer->createsGroup());
         if (renderer->isTransparent())