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

cc/trees/layer_tree_host_pixeltest_masks.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "build/build_config.h"
 #include "cc/layers/content_layer.h"
 #include "cc/layers/content_layer_client.h"
 #include "cc/layers/image_layer.h"
 #include "cc/layers/solid_color_layer.h"
 #include "cc/test/layer_tree_pixel_test.h"
 #include "cc/test/pixel_comparator.h"
 
 #if !defined(OS_ANDROID)
 
 namespace cc {
 namespace {
 
 class LayerTreeHostMasksPixelTest : public LayerTreePixelTest {};
 
-class MaskContentLayerClient : public cc::ContentLayerClient {
+class MaskContentLayerClient : public ContentLayerClient {
  public:
   MaskContentLayerClient() {}
   virtual ~MaskContentLayerClient() {}
 
   virtual void DidChangeLayerCanUseLCDText() OVERRIDE {}
 
   virtual void PaintContents(SkCanvas* canvas,
-                             gfx::Rect rect,
+                             const gfx::Rect& rect,
                              gfx::RectF* opaque_rect) OVERRIDE {
     SkPaint paint;
     paint.setStyle(SkPaint::kStroke_Style);
     paint.setStrokeWidth(SkIntToScalar(2));
     paint.setColor(SK_ColorWHITE);
 
     canvas->clear(SK_ColorTRANSPARENT);
-    while (!rect.IsEmpty()) {
-      rect.Inset(3, 3, 2, 2);
+    gfx::Rect inset_rect(rect);
+    while (!inset_rect.IsEmpty()) {
+      inset_rect.Inset(3, 3, 2, 2);
       canvas->drawRect(
-          SkRect::MakeXYWH(rect.x(), rect.y(), rect.width(), rect.height()),
+          SkRect::MakeXYWH(inset_rect.x(), inset_rect.y(),
+                           inset_rect.width(), inset_rect.height()),
           paint);
-      rect.Inset(3, 3, 2, 2);
+      inset_rect.Inset(3, 3, 2, 2);
     }
   }
 };
 
 TEST_F(LayerTreeHostMasksPixelTest, MaskOfLayer) {
   scoped_refptr<SolidColorLayer> background = CreateSolidColorLayer(
       gfx::Rect(200, 200), SK_ColorWHITE);
 
   scoped_refptr<SolidColorLayer> green = CreateSolidColorLayerWithBorder(
       gfx::Rect(50, 50, 100, 100), kCSSGreen, 1, SK_ColorBLACK);
@@ skipping 218 matching lines @@
   RunPixelTest(GL_WITH_BITMAP,
                background,
                base::FilePath(FILE_PATH_LITERAL(
                    "mask_of_replica_of_clipped_layer.png")));
 }
 
 }  // namespace
 }  // namespace cc
 
 #endif  // OS_ANDROID