Force use of and cache render surface.

cc/layers/layer.h

 // Copyright 2010 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.
 
 #ifndef CC_LAYERS_LAYER_H_
 #define CC_LAYERS_LAYER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 231 matching lines @@
   void SetTouchEventHandlerRegion(const Region& touch_event_handler_region);
   const Region& touch_event_handler_region() const {
     return inputs_.touch_event_handler_region;
   }
 
   void set_did_scroll_callback(
       const base::Callback<void(const gfx::ScrollOffset&)>& callback) {
     inputs_.did_scroll_callback = callback;
   }
 
-  void SetForceRenderSurfaceForTesting(bool force_render_surface);
-  bool force_render_surface_for_testing() const {
-    return force_render_surface_for_testing_;
-  }
+  void SetForceRenderSurface(bool force_render_surface);

[weiliangc, 2017/06/07 21:19:00]

Preferably a different name to distinguish old force_render_surface_for_testing_
behavior with current behavior. Since force_render_surface_for_testing_ doesn't
has same assumption about reuse.

Also add a comment saying what ui's force_render_surface does.

[wutao, 2017/06/09 02:31:32]

As discussed offline, will call the API cache_render_surface for now. There is a
comment in the ui::Layer.

+  bool force_render_surface() const { return force_render_surface_; }
 
   gfx::ScrollOffset CurrentScrollOffset() const {
     return inputs_.scroll_offset;
   }
 
   void SetDoubleSided(bool double_sided);
   bool double_sided() const { return inputs_.double_sided; }
 
   void SetShouldFlattenTransform(bool flatten);
   bool should_flatten_transform() const {
@@ skipping 342 matching lines @@
   int transform_tree_index_;
   int effect_tree_index_;
   int clip_tree_index_;
   int scroll_tree_index_;
   int property_tree_sequence_number_;
   gfx::Vector2dF offset_to_transform_parent_;
   bool should_flatten_transform_from_property_tree_ : 1;
   bool draws_content_ : 1;
   bool use_local_transform_for_backface_visibility_ : 1;
   bool should_check_backface_visibility_ : 1;
-  bool force_render_surface_for_testing_ : 1;
+  bool force_render_surface_ : 1;
   bool subtree_property_changed_ : 1;
   bool may_contain_video_ : 1;
   bool is_scroll_clip_layer_ : 1;
   bool needs_show_scrollbars_ : 1;
   // This value is valid only when LayerTreeHost::has_copy_request() is true
   bool subtree_has_copy_request_ : 1;
   SkColor safe_opaque_background_color_;
   std::unique_ptr<std::set<Layer*>> scroll_children_;
 
   std::unique_ptr<std::set<Layer*>> clip_children_;
 
   // These all act like draw properties, so don't need push properties.
   gfx::Rect visible_layer_rect_;
   size_t num_unclipped_descendants_;
 
   DISALLOW_COPY_AND_ASSIGN(Layer);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_LAYER_H_