mix-blend-mode implementation for accelerated layers

cc/trees/occlusion_tracker.cc

Index: cc/trees/occlusion_tracker.cc
diff --git a/cc/trees/occlusion_tracker.cc b/cc/trees/occlusion_tracker.cc
index 9fc26da566700ce9b46cb88974730ba722a6b155..5a22125388e30a6ee07adbc71b6b2dc87c006e03 100644
--- a/cc/trees/occlusion_tracker.cc
+++ b/cc/trees/occlusion_tracker.cc
@@ -238,6 +238,7 @@ void OcclusionTrackerBase<LayerType, RenderSurfaceType>::FinishedRenderTarget(
   if (finished_target->mask_layer() ||
       !SurfaceOpacityKnown(surface) ||
       surface->draw_opacity() < 1 ||
+      surface->has_blend_mode() ||
       target_is_only_for_copy_request ||
       finished_target->filters().HasFilterThatAffectsOpacity() ||
       finished_target->filter()) {
@@ -420,6 +421,9 @@ void OcclusionTrackerBase<LayerType, RenderSurfaceType>::
   if (!LayerOpacityKnown(layer) || layer->draw_opacity() < 1)
     return;
 
+  if (layer->has_blend_mode())
+    return;
+
   if (LayerIsInUnsorted3dRenderingContext(layer))
     return;