Force use of and cache render surface.

cc/quads/render_pass.h

 // Copyright 2011 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_QUADS_RENDER_PASS_H_
 #define CC_QUADS_RENDER_PASS_H_
 
 #include <stddef.h>
 
 #include <utility>
@@ skipping 69 matching lines @@
               const gfx::Rect& damage_rect,
               const gfx::Transform& transform_to_root_target);
 
   void SetAll(RenderPassId id,
               const gfx::Rect& output_rect,
               const gfx::Rect& damage_rect,
               const gfx::Transform& transform_to_root_target,
               const FilterOperations& filters,
               const FilterOperations& background_filters,
               const gfx::ColorSpace& color_space,
-              bool has_transparent_background);
+              bool has_transparent_background,
+              bool cache_render_surface,
+              bool has_damage_from_contributing_content);
 
   void AsValueInto(base::trace_event::TracedValue* dict) const;
 
   SharedQuadState* CreateAndAppendSharedQuadState();
 
   template <typename DrawQuadType>
   DrawQuadType* CreateAndAppendDrawQuad() {
     return quad_list.AllocateAndConstruct<DrawQuadType>();
   }
 
@@ skipping 21 matching lines @@
   // Post-processing filters, applied to the pixels showing through the
   // background of the render pass, from behind it.
   FilterOperations background_filters;
 
   // The color space into which content will be rendered for this render pass.
   gfx::ColorSpace color_space;
 
   // If false, the pixels in the render pass' texture are all opaque.
   bool has_transparent_background = true;
 
+  // If true we might reuse the texture if there is no damage.
+  bool cache_render_surface = false;
+  // A cumulated damage from contributing render surface or layer or surface

[vmpstr, 2017/07/13 18:01:03]

nit: Accumulated. Also, this comment isn't really saying what the bool holds.
Maybe say "Indicates whether there is accumulated damage ..."

[wutao, 2017/07/14 00:02:53]

Done.

+  // quad. Not including property changes on itself.
+  bool has_damage_from_contributing_content = false;
+
   // If non-empty, the renderer should produce a copy of the render pass'
   // contents as a bitmap, and give a copy of the bitmap to each callback in
   // this list. This property should not be serialized between compositors, as
   // it only makes sense in the root compositor.
   std::vector<std::unique_ptr<CopyOutputRequest>> copy_requests;
 
   QuadList quad_list;
   SharedQuadStateList shared_quad_state_list;
 
  protected:
   explicit RenderPass(size_t num_layers);
   RenderPass();
   RenderPass(size_t shared_quad_state_list_size, size_t quad_list_size);
 
  private:
   template <typename DrawQuadType>
   DrawQuadType* CopyFromAndAppendTypedDrawQuad(const DrawQuad* quad) {
     return quad_list.AllocateAndCopyFrom(DrawQuadType::MaterialCast(quad));
   }
 
   DISALLOW_COPY_AND_ASSIGN(RenderPass);
 };
 
 using RenderPassList = std::vector<std::unique_ptr<RenderPass>>;
 
 }  // namespace cc
 
 #endif  // CC_QUADS_RENDER_PASS_H_