mix-blend-mode implementation for accelerated layers

cc/layers/layer_impl.cc

Index: cc/layers/layer_impl.cc
diff --git a/cc/layers/layer_impl.cc b/cc/layers/layer_impl.cc
index 1ecd642d50bd4963ddd9db00fcc0af63597e0342..b68779200dd61efd9df6a97fd0c084131d5e782d 100644
--- a/cc/layers/layer_impl.cc
+++ b/cc/layers/layer_impl.cc
@@ -50,6 +50,8 @@ LayerImpl::LayerImpl(LayerTreeImpl* tree_impl, int id)
       masks_to_bounds_(false),
       contents_opaque_(false),
       opacity_(1.0),
+      blend_mode_(SkXfermode::kSrcOver_Mode),
+      is_root_for_isolated_group_(false),
       preserves_3d_(false),
       use_parent_backface_visibility_(false),
       draw_checkerboard_for_missing_tiles_(false),
@@ -243,7 +245,8 @@ scoped_ptr<SharedQuadState> LayerImpl::CreateSharedQuadState() const {
                 draw_properties_.visible_content_rect,
                 draw_properties_.clip_rect,
                 draw_properties_.is_clipped,
-                draw_properties_.opacity);
+                draw_properties_.opacity,
+                blend_mode_);
   return state.Pass();
 }
 
@@ -508,6 +511,8 @@ void LayerImpl::PushPropertiesTo(LayerImpl* layer) {
   layer->SetTouchEventHandlerRegion(touch_event_handler_region_);
   layer->SetContentsOpaque(contents_opaque_);
   layer->SetOpacity(opacity_);
+  layer->SetBlendMode(blend_mode_);
+  layer->SetIsRootForIsolatedGroup(is_root_for_isolated_group_);
   layer->SetPosition(position_);
   layer->SetIsContainerForFixedPositionLayers(
       is_container_for_fixed_position_layers_);
@@ -864,6 +869,22 @@ bool LayerImpl::OpacityIsAnimatingOnImplOnly() const {
   return opacity_animation && opacity_animation->is_impl_only();
 }
 
+void LayerImpl::SetBlendMode(SkXfermode::Mode blendMode) {
+  if (blend_mode_ == blendMode)
+    return;
+
+  blend_mode_ = blendMode;
+  NoteLayerSurfacePropertyChanged();
+}
+
+void LayerImpl::SetIsRootForIsolatedGroup(bool root) {
+  if (is_root_for_isolated_group_ == root)
+    return;
+
+  is_root_for_isolated_group_ = root;
+  NoteLayerSurfacePropertyChanged();

[enne (OOO), 2013/10/11 18:14:35]

Should this really cause damage? It seems to me that the damage should all be
from the child's surface that is blending and not on the root for the isolated
group, and this can be removed.

[rosca, 2013/10/16 14:54:47]

Done.

+}
+
 void LayerImpl::SetPosition(gfx::PointF position) {
   if (position_ == position)
     return;
@@ -1260,6 +1281,9 @@ CompositingReasonsAsValue(CompositingReasons reasons) {
   if (reasons & kCompositingReasonOutOfFlowClipping)
     reason_list->AppendString("Has clipping ancestor");
 
+  if (reasons & kCompositingReasonIsolateCompositedDescendants)
+    reason_list->AppendString("Should isolate composited dscendants");
+
   return reason_list.PassAs<base::Value>();
 }