cc: Do not cleanup tiles with raster tasks.

cc/test/fake_picture_layer_tiling_client.h

Index: cc/test/fake_picture_layer_tiling_client.h
diff --git a/cc/test/fake_picture_layer_tiling_client.h b/cc/test/fake_picture_layer_tiling_client.h
index 6bdede04bbfccaca3520a4b4475fe07d1412dae9..f46cc844212120843bf0675e586777ee65309b0c 100644
--- a/cc/test/fake_picture_layer_tiling_client.h
+++ b/cc/test/fake_picture_layer_tiling_client.h
@@ -36,6 +36,7 @@ class FakePictureLayerTilingClient : public PictureLayerTilingClient {
   virtual const Region* GetInvalidation() OVERRIDE;
   virtual const PictureLayerTiling* GetTwinTiling(
       const PictureLayerTiling* tiling) const OVERRIDE;
+  virtual WhichTree GetTree() const OVERRIDE;
 
   void set_twin_tiling(PictureLayerTiling* tiling) { twin_tiling_ = tiling; }
   void set_text_rect(const gfx::Rect& rect) { text_rect_ = rect; }
@@ -50,6 +51,7 @@ class FakePictureLayerTilingClient : public PictureLayerTilingClient {
   void set_skewport_extrapolation_limit_in_content_pixels(int limit) {
     skewport_extrapolation_limit_in_content_pixels_ = limit;
   }
+  void set_tree(WhichTree tree) { tree_ = tree; }
 
   TileManager* tile_manager() const {
     return tile_manager_.get();
@@ -68,6 +70,7 @@ class FakePictureLayerTilingClient : public PictureLayerTilingClient {
   size_t max_tiles_for_interest_area_;
   float skewport_target_time_in_seconds_;
   int skewport_extrapolation_limit_in_content_pixels_;
+  WhichTree tree_;
 };
 
 }  // namespace cc