cc: Fix BytesPerPixel issue and refactor.

cc/tiles/tile.cc

Index: cc/tiles/tile.cc
diff --git a/cc/tiles/tile.cc b/cc/tiles/tile.cc
index 6052e5e0457e0f41cca41eab900166237f0bd6ee..640eec4566e5aa58d49b0959fc4b5461e1854307 100644
--- a/cc/tiles/tile.cc
+++ b/cc/tiles/tile.cc
@@ -69,10 +69,10 @@ void Tile::AsValueInto(base::trace_event::TracedValue* value) const {
 
 size_t Tile::GPUMemoryUsageInBytes() const {
   if (draw_info_.resource_) {
-    // We can use UncheckedSizeInBytes, since the tile size is determined by the
+    // We can use SizeInBytes, since the tile size is determined by the
     // compositor.
-    return Resource::UncheckedMemorySizeBytes(draw_info_.resource_->size(),
-                                              draw_info_.resource_->format());
+    return ResourceUtil::SizeInBytes(draw_info_.resource_->size(),
+                                     draw_info_.resource_->format());
   }
   return 0;
 }