Allow task pools to reason about transparency.

cc/layers/picture_layer_impl.cc

 // Copyright 2012 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/picture_layer_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <set>
@@ skipping 624 matching lines @@
 }
 
 ScopedTilePtr PictureLayerImpl::CreateTile(const Tile::CreateInfo& info) {
   int flags = 0;
 
   // We don't handle solid color masks, so we shouldn't bother analyzing those.
   // Otherwise, always analyze to maximize memory savings.
   if (!is_mask_)
     flags = Tile::USE_PICTURE_ANALYSIS;
 
+  if (contents_opaque())
+    flags |= Tile::IS_OPAQUE;
+
   return layer_tree_impl()->tile_manager()->CreateTile(
       info, id(), layer_tree_impl()->source_frame_number(), flags);
 }
 
 const Region* PictureLayerImpl::GetPendingInvalidation() {
   if (layer_tree_impl()->IsPendingTree())
     return &invalidation_;
   if (layer_tree_impl()->IsRecycleTree())
     return nullptr;
   DCHECK(layer_tree_impl()->IsActiveTree());
@@ skipping 588 matching lines @@
 
 bool PictureLayerImpl::IsOnActiveOrPendingTree() const {
   return !layer_tree_impl()->IsRecycleTree();
 }
 
 bool PictureLayerImpl::HasValidTilePriorities() const {
   return IsOnActiveOrPendingTree() && IsDrawnRenderSurfaceLayerListMember();
 }
 
 }  // namespace cc