Force use of and cache render surface.

cc/quads/render_pass.h

Index: cc/quads/render_pass.h
diff --git a/cc/quads/render_pass.h b/cc/quads/render_pass.h
index 0ad8debc8928f0c5d07506d39a0dbd11aa6e070c..815bf9ab5b4acb41a631a821a8ba4bebf6ab5edf 100644
--- a/cc/quads/render_pass.h
+++ b/cc/quads/render_pass.h
@@ -85,7 +85,8 @@ class CC_EXPORT RenderPass {
               const FilterOperations& filters,
               const FilterOperations& background_filters,
               const gfx::ColorSpace& color_space,
-              bool has_transparent_background);
+              bool has_transparent_background,
+              bool force_render_surface);
 
   void AsValueInto(base::trace_event::TracedValue* dict) const;
 
@@ -127,6 +128,8 @@ class CC_EXPORT RenderPass {
   // If false, the pixels in the render pass' texture are all opaque.
   bool has_transparent_background = true;
 
+  bool force_render_surface = false;

[danakj, 2017/05/11 19:56:50]

Please add documentation for new fields added to structs like this

[wutao, 2017/05/26 03:38:22]

Done.

+
   // 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