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

ash/wm/system_modal_container_layout_manager.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 "ash/wm/system_modal_container_layout_manager.h"
 
 #include "ash/ash_switches.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/wm/system_modal_container_event_filter.h"
@@ skipping 61 matching lines @@
 
 void SystemModalContainerLayoutManager::OnWindowResized() {
   if (modal_background_) {
     // Note: we have to set the entire bounds with the screen offset.
     modal_background_->SetBounds(
         Shell::GetScreen()->GetDisplayNearestWindow(container_).bounds());
   }
   if (!modal_windows_.empty()) {
     aura::Window::Windows::iterator it = modal_windows_.begin();
     for (it = modal_windows_.begin(); it != modal_windows_.end(); ++it) {
-      (*it)->SetBounds((*it)->bounds().AdjustToFit(container_->bounds()));
+      gfx::Rect bounds = (*it)->bounds();
+      bounds.AdjustToFit(container_->bounds());
+      (*it)->SetBounds(bounds);
     }
   }
 }
 
 void SystemModalContainerLayoutManager::OnWindowAddedToLayout(
     aura::Window* child) {
   DCHECK((modal_background_ && child == modal_background_->GetNativeView()) ||
          child->type() == aura::client::WINDOW_TYPE_NORMAL ||
          child->type() == aura::client::WINDOW_TYPE_POPUP);
   child->AddObserver(this);
@@ skipping 135 matching lines @@
   aura::Window::Windows::iterator it =
       std::find(modal_windows_.begin(), modal_windows_.end(), window);
   if (it != modal_windows_.end())
     modal_windows_.erase(it);
 
   Shell::GetInstance()->OnModalWindowRemoved(window);
 }
 
 }  // namespace internal
 }  // namespace ash