cc: Don't sync tilings to layers that don't draw content.

cc/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/picture_layer_impl.h"
 
 #include "base/time.h"
 #include "cc/append_quads_data.h"
 #include "cc/checkerboard_draw_quad.h"
 #include "cc/debug_border_draw_quad.h"
@@ skipping 403 matching lines @@
         continue;
       gfx::Rect layer_rect = pile_->tile_bounds(x, y);
       tilings_->CreateTilesFromLayerRect(layer_rect);
     }
   }
 }
 
 void PictureLayerImpl::SyncTiling(
     const PictureLayerTiling* tiling,
     const Region& pending_layer_invalidation) {
+  if (!drawsContent())
+    return;
   tilings_->Clone(tiling, pending_layer_invalidation);
 }
 
 void PictureLayerImpl::SetIsMask(bool is_mask) {
   if (is_mask_ == is_mask)
     return;
   is_mask_ = is_mask;
   if (tilings_)
     tilings_->RemoveAllTiles();
 }
@@ skipping 293 matching lines @@
   return twin;
 }
 
 void PictureLayerImpl::getDebugBorderProperties(
     SkColor* color, float* width) const {
   *color = DebugColors::TiledContentLayerBorderColor();
   *width = DebugColors::TiledContentLayerBorderWidth(layerTreeImpl());
 }
 
 }  // namespace cc