cc: RenderSurfaceImpl tile mask layer.

cc/trees/draw_property_utils.cc

 // Copyright 2014 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/trees/draw_property_utils.h"
 
 #include <stddef.h>
 
 #include <vector>
 
@@ skipping 1006 matching lines @@
         gfx::Rect(layer->bounds()));
     layer->draw_properties().drawable_content_rect = LayerDrawableContentRect(
         layer, bounds_in_target_space, layer->draw_properties().clip_rect);
   }
 }
 
 void ComputeMaskDrawProperties(LayerImpl* mask_layer,
                                const PropertyTrees* property_trees) {
   // Mask draw properties are used only for rastering, so most of the draw
   // properties computed for other layers are not needed.
+  // Draw transform of a mask layer has to be a 2d scale.
+  // TODO(sunxd): the draw transform of a mask layer misses the "scale to fit"
+  // factor from mask layer to its parent. So does the screen space transform.
+  // It does not cause a problem because currently we only have 1:1 mask layer.
+  mask_layer->draw_properties().target_space_transform = DrawTransform(
+      mask_layer, property_trees->transform_tree, property_trees->effect_tree);
   mask_layer->draw_properties().screen_space_transform =
       ScreenSpaceTransformInternal(mask_layer,
                                    property_trees->transform_tree);
   mask_layer->draw_properties().visible_layer_rect =
       gfx::Rect(mask_layer->bounds());
 }
 
 void ComputeSurfaceDrawProperties(PropertyTrees* property_trees,
                                   RenderSurfaceImpl* render_surface,
                                   const bool use_layer_lists) {
@@ skipping 40 matching lines @@
 void UpdateElasticOverscroll(PropertyTrees* property_trees,
                              const Layer* overscroll_elasticity_layer,
                              const gfx::Vector2dF& elastic_overscroll) {
   UpdateElasticOverscrollInternal(property_trees, overscroll_elasticity_layer,
                                   elastic_overscroll);
 }
 
 }  // namespace draw_property_utils
 
 }  // namespace cc