Add command-line flag to force compositor framerate.

ui/compositor/compositor_switches.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/compositor/compositor_switches.h"
 
 #include "base/command_line.h"
 
 namespace switches {
 
 // Enable compositing individual elements via hardware overlays when
 // permitted by device.
 // Setting the flag to "single-fullscreen" will try to promote a single
 // fullscreen overlay and use it as main framebuffer where possible.
 const char kEnableHardwareOverlays[] = "enable-hardware-overlays";
 
 // Forces tests to produce pixel output when they normally wouldn't.
 const char kEnablePixelOutputInTests[] = "enable-pixel-output-in-tests";
 
+// Limits the compositor to output a certain number of frames per second,
+// maximum.
+const char kLimitFps[] = "limit-fps";
+
 // Disable partial swap which is needed for some OpenGL drivers / emulators.
 const char kUIDisablePartialSwap[] = "ui-disable-partial-swap";
 
 const char kUIEnableRGBA4444Textures[] = "ui-enable-rgba-4444-textures";
 
 const char kUIEnableZeroCopy[] = "ui-enable-zero-copy";
 
 const char kUIShowPaintRects[] = "ui-show-paint-rects";
 
 const char kUISlowAnimations[] = "ui-slow-animations";
 
 }  // namespace switches
 
 namespace ui {
 
 bool IsUIZeroCopyEnabled() {
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
   return command_line.HasSwitch(switches::kUIEnableZeroCopy);
 }
 
 }  // namespace ui