cc: Avoid expensive RenderingStats collection.

cc/tiled_layer.cc

Index: cc/tiled_layer.cc
diff --git a/cc/tiled_layer.cc b/cc/tiled_layer.cc
index 2d7d8270d0bdbe0b3c5748130bb0aefc67c86455..464e4f4fe1b1637aa4625619253712424ea5751a 100644
--- a/cc/tiled_layer.cc
+++ b/cc/tiled_layer.cc
@@ -309,7 +309,7 @@ bool TiledLayer::tileOnlyNeedsPartialUpdate(UpdatableTile* tile)
     return !tile->dirtyRect.Contains(m_tiler->tileRect(tile)) && tile->managedResource()->haveBackingTexture();
 }
 
-bool TiledLayer::updateTiles(int left, int top, int right, int bottom, ResourceUpdateQueue& queue, const OcclusionTracker* occlusion, RenderingStats& stats, bool& didPaint)
+bool TiledLayer::updateTiles(int left, int top, int right, int bottom, ResourceUpdateQueue& queue, const OcclusionTracker* occlusion, RenderingStats* stats, bool& didPaint)
 {
     didPaint = false;
     createUpdaterIfNeeded();
@@ -427,7 +427,7 @@ gfx::Rect TiledLayer::markTilesForUpdate(int left, int top, int right, int botto
     return paintRect;
 }
 
-void TiledLayer::updateTileTextures(const gfx::Rect& paintRect, int left, int top, int right, int bottom, ResourceUpdateQueue& queue, const OcclusionTracker* occlusion, RenderingStats& stats)
+void TiledLayer::updateTileTextures(const gfx::Rect& paintRect, int left, int top, int right, int bottom, ResourceUpdateQueue& queue, const OcclusionTracker* occlusion, RenderingStats* stats)
 {
     // The updateRect should be in layer space. So we have to convert the paintRect from content space to layer space.
     float widthScale = bounds().width() / static_cast<float>(contentBounds().width());
@@ -640,7 +640,7 @@ void TiledLayer::updateScrollPrediction()
     m_previousVisibleRect = visibleContentRect();
 }
 
-void TiledLayer::update(ResourceUpdateQueue& queue, const OcclusionTracker* occlusion, RenderingStats& stats)
+void TiledLayer::update(ResourceUpdateQueue& queue, const OcclusionTracker* occlusion, RenderingStats* stats)
 {
     DCHECK(!m_skipsDraw && !m_failedUpdate); // Did resetUpdateState get skipped?