cc: Don't pass simple well-defined classes by reference.

cc/quads/shared_quad_state.cc

Index: cc/quads/shared_quad_state.cc
diff --git a/cc/quads/shared_quad_state.cc b/cc/quads/shared_quad_state.cc
index 2b9470dd38dbb5b2f65b5671226868a26cac93f1..7bfb2b440f378b9333383add131a297eabb71fa3 100644
--- a/cc/quads/shared_quad_state.cc
+++ b/cc/quads/shared_quad_state.cc
@@ -20,9 +20,9 @@ scoped_ptr<SharedQuadState> SharedQuadState::Copy() const {
 
 void SharedQuadState::SetAll(
     const gfx::Transform& content_to_target_transform,
-    const gfx::Size content_bounds,
-    const gfx::Rect& visible_content_rect,
-    const gfx::Rect& clip_rect,
+    gfx::Size content_bounds,
+    gfx::Rect visible_content_rect,
+    gfx::Rect clip_rect,
     bool is_clipped,
     float opacity) {
   this->content_to_target_transform = content_to_target_transform;