Revert of List all child surfaces (including occluded) in CompositorFrame

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 6df7e6ba0f870895d8b12c07389a3b65e38d977d..738aeec2a0bc003aa6ed5859f440cdc2049a0e25 100644
--- a/cc/surfaces/surface_aggregator.h
+++ b/cc/surfaces/surface_aggregator.h
@@ -60,15 +60,6 @@
     gfx::Rect rect;
   };
 
-  struct PrewalkResult {
-    PrewalkResult();
-    ~PrewalkResult();
-    bool has_copy_requests = false;
-    // This is the set of Surfaces that were referenced by another Surface, but
-    // not included in a SurfaceDrawQuad.
-    std::set<SurfaceId> undrawn_surfaces;
-  };
-
   ClipData CalculateClipRect(const ClipData& surface_clip,
                              const ClipData& quad_clip,
                              const gfx::Transform& target_transform);
@@ -92,8 +83,7 @@
       const ClipData& clip_rect,
       RenderPass* dest_pass,
       SurfaceId surface_id);
-  gfx::Rect PrewalkTree(SurfaceId surface_id, PrewalkResult* result);
-  void CopyUndrawnSurfaces(PrewalkResult* prewalk);
+  gfx::Rect PrewalkTree(SurfaceId surface_id);
   void CopyPasses(const DelegatedFrameData* frame_data, Surface* surface);
 
   // Remove Surfaces that were referenced before but aren't currently