Force use of and cache render surface.

cc/surfaces/surface_aggregator.h

Index: cc/surfaces/surface_aggregator.h
diff --git a/cc/surfaces/surface_aggregator.h b/cc/surfaces/surface_aggregator.h
index 28aeb493bcc7f18150ec99dbbf1506f5c277ecac..799d04ea7dff10460543741b9d0d5b9dca1de70e 100644
--- a/cc/surfaces/surface_aggregator.h
+++ b/cc/surfaces/surface_aggregator.h
@@ -130,7 +130,7 @@ class CC_SURFACES_EXPORT SurfaceAggregator {
   // child surfaces.
   void ProcessAddedAndRemovedSurfaces();
 
-  void PropagateCopyRequestPasses();
+  void PropagatePasses(base::flat_set<int>* passes);
 
   int ChildIdForSurface(Surface* surface);
   gfx::Rect DamageRectForSurface(const Surface* surface,
@@ -189,6 +189,11 @@ class CC_SURFACES_EXPORT SurfaceAggregator {
   // should not have their damage rects clipped to the root damage rect.
   base::flat_set<int> copy_request_passes_;
 
+  // This is the set of aggregated pass ids that are drawn by force render
+  // surface, so should not have their damage rects clipped to the root damage
+  // rect.
+  base::flat_set<int> force_render_surface_passes_;
+
   // This maps each aggregated pass id to the set of (aggregated) pass ids
   // that its RenderPassDrawQuads depend on
   base::flat_map<int, base::flat_set<int>> render_pass_dependencies_;
@@ -200,6 +205,10 @@ class CC_SURFACES_EXPORT SurfaceAggregator {
   // This is valid during Aggregate after PrewalkTree is called.
   bool has_copy_requests_;
 
+  // True if the frame that's currently being aggregated has force render
+  // surface. This is valid during Aggregate after PrewalkTree is called.
+  bool has_force_render_surfaces_;
+
   // Tracks UMA stats for SurfaceDrawQuads during a call to Aggregate().
   SurfaceDrawQuadUmaStats uma_stats_;