Make gfx::Rect class operations consistently mutate the class they are called on.

ui/views/animation/bounds_animator_unittest.cc

 // Copyright (c) 2012 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 "ui/views/animation/bounds_animator.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/base/animation/slide_animation.h"
 #include "ui/base/animation/test_animation_delegate.h"
 #include "ui/views/view.h"
@@ skipping 58 matching lines @@
 bool OwnedDelegate::canceled_ = false;
 
 class TestView : public View {
  public:
   TestView() {}
 
   virtual void SchedulePaintInRect(const gfx::Rect& r) OVERRIDE {
     if (dirty_rect_.IsEmpty())
       dirty_rect_ = r;
     else
-      dirty_rect_ = dirty_rect_.Union(r);
+      dirty_rect_.Union(r);
   }
 
   const gfx::Rect& dirty_rect() const { return dirty_rect_; }
 
  private:
   gfx::Rect dirty_rect_;
 
   DISALLOW_COPY_AND_ASSIGN(TestView);
 };
 
@@ skipping 32 matching lines @@
 
   // Run the message loop; the delegate exits the loop when the animation is
   // done.
   MessageLoop::current()->Run();
 
   // Make sure the bounds match of the view that was animated match.
   EXPECT_EQ(target_bounds, child()->bounds());
 
   // The parent should have been told to repaint as the animation progressed.
   // The resulting rect is the union of the original and target bounds.
-  EXPECT_EQ(target_bounds.Union(initial_bounds), parent()->dirty_rect());
+  target_bounds.Union(initial_bounds);
+  EXPECT_EQ(target_bounds, parent()->dirty_rect());
 }
 
 // Make sure an AnimationDelegate is deleted when canceled.
 TEST_F(BoundsAnimatorTest, DeleteDelegateOnCancel) {
   animator()->AnimateViewTo(child(), gfx::Rect(0, 0, 10, 10));
   animator()->SetAnimationDelegate(child(), new OwnedDelegate(), true);
 
   animator()->Cancel();
 
   // The animator should no longer be animating.
@@ skipping 28 matching lines @@
 
   // Shouldn't be animating now.
   EXPECT_FALSE(animator()->IsAnimating());
 
   // Stopping should both cancel the delegate and delete it.
   EXPECT_TRUE(OwnedDelegate::GetAndClearDeleted());
   EXPECT_TRUE(OwnedDelegate::GetAndClearCanceled());
 }
 
 }  // namespace views