ui: Make gfx::Size::Scale() mutate the class. Add gfx::ScaleSize() similar to Rect/Point.

ash/display/multi_display_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/display/multi_display_manager.h"
 
 #include <string>
 #include <vector>
 
 #include "ash/display/display_controller.h"
@@ skipping 431 matching lines @@
   OnNativeDisplaysChanged(new_displays);
 }
 
 void MultiDisplayManager::ScaleDisplayImpl() {
   DCHECK(!displays_.empty());
   std::vector<gfx::Display> new_displays;
   for (DisplayList::const_iterator iter = displays_.begin();
        iter != displays_.end(); ++iter) {
     gfx::Display display = *iter;
     float factor = display.device_scale_factor() == 1.0f ? 2.0f : 1.0f;
-    display.SetScaleAndBounds(
-        factor, gfx::Rect(display.bounds_in_pixel().origin(),
-                          gfx::ToFlooredSize(display.size().Scale(factor))));
+    gfx::Point display_origin = display.bounds_in_pixel().origin();
+    gfx::Size display_size = gfx::ToFlooredSize(
+        gfx::ScaleSize(display.size(), factor));
+    display.SetScaleAndBounds(factor, gfx::Rect(display_origin, display_size));
     new_displays.push_back(display);
   }
   OnNativeDisplaysChanged(new_displays);
 }
 
 gfx::Display& MultiDisplayManager::FindDisplayForRootWindow(
     const aura::RootWindow* root_window) {
   int64 id = root_window->GetProperty(kDisplayIdKey);
   // if id is |kInvaildDisplayID|, it's being deleted.
   DCHECK(id != gfx::Display::kInvalidDisplayID);
@@ skipping 102 matching lines @@
   DisplayList::iterator iter_to_update = to_update->begin();
   DisplayList::const_iterator iter = displays_.begin();
   for (; iter != displays_.end() && iter_to_update != to_update->end();
        ++iter, ++iter_to_update) {
     (*iter_to_update).set_id((*iter).id());
   }
 }
 
 }  // namespace internal
 }  // namespace ash