cc: Fix const value pattern by replacing it by non-const or reference.

cc/layers/scrollbar_layer_unittest.cc

Index: cc/layers/scrollbar_layer_unittest.cc
diff --git a/cc/layers/scrollbar_layer_unittest.cc b/cc/layers/scrollbar_layer_unittest.cc
index 2cc8c05f24a04d54f7e50af4f4fb8c0500f06bd8..95447c13fa68ef2c25f8146dd08ccf9f6f9b8d70 100644
--- a/cc/layers/scrollbar_layer_unittest.cc
+++ b/cc/layers/scrollbar_layer_unittest.cc
@@ -1029,7 +1029,7 @@ TEST_F(ScrollbarLayerTestResourceCreationAndRelease, TestResourceUpdate) {
 
 class ScaledScrollbarLayerTestResourceCreation : public ScrollbarLayerTest {
  public:
-  void TestResourceUpload(const float test_scale) {
+  void TestResourceUpload(float test_scale) {
     gfx::Point scrollbar_location(0, 185);
     scoped_refptr<Layer> layer_tree_root = Layer::Create();
     scoped_refptr<Layer> content_layer = Layer::Create();
@@ -1098,7 +1098,7 @@ TEST_F(ScaledScrollbarLayerTestResourceCreation, ScaledResourceUpload) {
 
 class ScaledScrollbarLayerTestScaledRasterization : public ScrollbarLayerTest {
  public:
-  void TestScale(const gfx::Rect scrollbar_rect, const float test_scale) {
+  void TestScale(const gfx::Rect& scrollbar_rect, float test_scale) {
     bool paint_during_update = true;
     bool has_thumb = false;
     scoped_refptr<Layer> layer_tree_root = Layer::Create();