cc: Remove OverdrawMetrics and --trace-overdraw flag.

cc/layers/tiled_layer.cc

Index: cc/layers/tiled_layer.cc
diff --git a/cc/layers/tiled_layer.cc b/cc/layers/tiled_layer.cc
index 26a3e5cd5851e9d9711ca4fb644d36ff5c42a809..5607496b79e028e449bb534ab2523eeb7944099e 100644
--- a/cc/layers/tiled_layer.cc
+++ b/cc/layers/tiled_layer.cc
@@ -10,7 +10,6 @@
 #include "base/auto_reset.h"
 #include "base/basictypes.h"
 #include "build/build_config.h"
-#include "cc/debug/overdraw_metrics.h"
 #include "cc/layers/layer_impl.h"
 #include "cc/layers/tiled_layer_impl.h"
 #include "cc/resources/layer_updater.h"
@@ -342,9 +341,6 @@ bool TiledLayer::UpdateTiles(int left,
   MarkTilesForUpdate(
     &update_rect, &paint_rect, left, top, right, bottom, ignore_occlusions);
 
-  if (occlusion)
-    occlusion->overdraw_metrics()->DidPaint(paint_rect);
-
   if (paint_rect.IsEmpty())
     return true;
 
@@ -360,12 +356,6 @@ void TiledLayer::MarkOcclusionsAndRequestTextures(
     int right,
     int bottom,
     const OcclusionTracker<Layer>* occlusion) {
-  // There is some difficult dependancies between occlusions, recording
-  // occlusion metrics and requesting memory so those are encapsulated in this
-  // function: - We only want to call RequestLate on unoccluded textures (to
-  // preserve memory for other layers when near OOM).  - We only want to record
-  // occlusion metrics if all memory requests succeed.
-
   int occluded_tile_count = 0;
   bool succeeded = true;
   for (int j = top; j <= bottom; ++j) {
@@ -390,11 +380,6 @@ void TiledLayer::MarkOcclusionsAndRequestTextures(
       }
     }
   }
-
-  if (!succeeded)
-    return;
-  if (occlusion)
-    occlusion->overdraw_metrics()->DidCullTilesForUpload(occluded_tile_count);
 }
 
 bool TiledLayer::HaveTexturesForTiles(int left,
@@ -566,10 +551,6 @@ void TiledLayer::UpdateTileTextures(const gfx::Rect& update_rect,
 
       tile->updater_resource()->Update(
           queue, source_rect, dest_offset, tile->partial_update);
-      if (occlusion) {
-        occlusion->overdraw_metrics()->
-            DidUpload(gfx::Transform(), source_rect, tile->opaque_rect());
-      }
     }
   }
 }