cc : Track ids for which active opacity always wins on property trees

cc/layers/painted_scrollbar_layer.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/layers/painted_scrollbar_layer.h"
 
 #include <algorithm>
 
 #include "base/auto_reset.h"
 #include "cc/base/math_util.h"
@@ skipping 52 matching lines @@
     return;
 
   scroll_layer_id_ = layer_id;
   SetNeedsFullTreeSync();
 }
 
 bool PaintedScrollbarLayer::OpacityCanAnimateOnImplThread() const {
   return scrollbar_->IsOverlay();
 }
 
+bool PaintedScrollbarLayer::AlwaysUseActiveTreeOpacity() const {
+  return true;
+}
+
 ScrollbarOrientation PaintedScrollbarLayer::orientation() const {
   return scrollbar_->Orientation();
 }
 
 int PaintedScrollbarLayer::MaxTextureSize() {
   DCHECK(layer_tree_host());
   return layer_tree_host()->GetRendererCapabilities().max_texture_size;
 }
 
 float PaintedScrollbarLayer::ClampScaleToMaxTextureSize(float scale) {
@@ skipping 217 matching lines @@
 
   scrollbar_->PaintPart(&skcanvas, part, layer_rect);
   // Make sure that the pixels are no longer mutable to unavoid unnecessary
   // allocation and copying.
   skbitmap.setImmutable();
 
   return UIResourceBitmap(skbitmap);
 }
 
 }  // namespace cc