cc: Record statistics about approximated content.

cc/layers/append_quads_data.h

Index: cc/layers/append_quads_data.h
diff --git a/cc/layers/append_quads_data.h b/cc/layers/append_quads_data.h
index 5e19731fd286986a60958a62f394c7defa9ae9ea..7c6768f6630ea9480d604274c65c59de1bdfd774 100644
--- a/cc/layers/append_quads_data.h
+++ b/cc/layers/append_quads_data.h
@@ -14,17 +14,25 @@ struct AppendQuadsData {
   AppendQuadsData()
       : had_incomplete_tile(false),
         num_missing_tiles(0),
+        visible_content_area(0),
+        approximated_visible_content_area(0),
         render_pass_id(0, 0) {}
 
   explicit AppendQuadsData(RenderPass::Id render_pass_id)
       : had_incomplete_tile(false),
         num_missing_tiles(0),
+        visible_content_area(0),
+        approximated_visible_content_area(0),
         render_pass_id(render_pass_id) {}
 
   // Set by the layer appending quads.
   bool had_incomplete_tile;
   // Set by the layer appending quads.
   int64 num_missing_tiles;
+  // Set by the layer appending quads.
+  int64 visible_content_area;
+  // Set by the layer appending quads.
+  int64 approximated_visible_content_area;
   // Given to the layer appending quads.
   const RenderPass::Id render_pass_id;
 };