[#2] Pass gfx structs by const ref (gfx::Rect, gfx::RectF)

cc/resources/bitmap_skpicture_content_layer_updater.cc

Index: cc/resources/bitmap_skpicture_content_layer_updater.cc
diff --git a/cc/resources/bitmap_skpicture_content_layer_updater.cc b/cc/resources/bitmap_skpicture_content_layer_updater.cc
index cc839a60eee2a8de9d4b69af3d9492d424dfd0ca..0ca48b428990a020f03bb5ca7080e5a758408fd7 100644
--- a/cc/resources/bitmap_skpicture_content_layer_updater.cc
+++ b/cc/resources/bitmap_skpicture_content_layer_updater.cc
@@ -21,7 +21,7 @@ BitmapSkPictureContentLayerUpdater::Resource::Resource(
 
 void BitmapSkPictureContentLayerUpdater::Resource::Update(
     ResourceUpdateQueue* queue,
-    gfx::Rect source_rect,
+    const gfx::Rect& source_rect,
     gfx::Vector2d dest_offset,
     bool partial_update) {
   bitmap_.setConfig(
@@ -70,7 +70,7 @@ BitmapSkPictureContentLayerUpdater::CreateResource(
 
 void BitmapSkPictureContentLayerUpdater::PaintContentsRect(
     SkCanvas* canvas,
-    gfx::Rect source_rect) {
+    const gfx::Rect& source_rect) {
   // Translate the origin of content_rect to that of source_rect.
   canvas->translate(content_rect().x() - source_rect.x(),
                     content_rect().y() - source_rect.y());