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

content/browser/renderer_host/render_widget_host_view_mac.mm

 // 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 "content/browser/renderer_host/render_widget_host_view_mac.h"
 
 #include <QuartzCore/QuartzCore.h>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 840 matching lines @@
     const gfx::Rect& src_subrect,
     const gfx::Size& dst_size,
     const base::Callback<void(bool)>& callback,
     skia::PlatformBitmap* output) {
   base::ScopedClosureRunner scoped_callback_runner(base::Bind(callback, false));
   if (!compositing_iosurface_.get() ||
       !compositing_iosurface_->HasIOSurface())
     return;
 
   float scale = ScaleFactor(cocoa_view_);
-  gfx::Size dst_pixel_size = gfx::ToFlooredSize(dst_size.Scale(scale));
+  gfx::Size dst_pixel_size = gfx::ToFlooredSize(
+      gfx::ScaleSize(dst_size, scale));
   if (!output->Allocate(
       dst_pixel_size.width(), dst_pixel_size.height(), true))
     return;
   scoped_callback_runner.Release();
 
   // Convert |src_subrect| from the views coordinate (upper-left origin) into
   // the OpenGL coordinate (lower-left origin).
   gfx::Rect src_gl_subrect = src_subrect;
   src_gl_subrect.set_y(GetViewBounds().height() - src_subrect.bottom());
 
@@ skipping 2488 matching lines @@
   if (!string) return NO;
 
   // If the user is currently using an IME, confirm the IME input,
   // and then insert the text from the service, the same as TextEdit and Safari.
   [self confirmComposition];
   [self insertText:string];
   return YES;
 }
 
 @end