Make disable vsync run the renderer independently

ui/gl/gl_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 "base/macros.h"
 #include "ui/gl/gl_switches.h"
 
 namespace gl {
 
 const char kGLImplementationDesktopName[]     = "desktop";
@@ skipping 12 matching lines @@
 
 }  // namespace gl
 
 namespace switches {
 
 // Disables use of D3D11.
 const char kDisableD3D11[]                  = "disable-d3d11";
 
 // Stop the GPU from synchronizing on the vsync before presenting.
 // We can select from the options below:
-//  beginframe : Next frame can start without any delay on cc::scheduler.
-//  gpu : Disable gpu vsync.
+//  beginframe: Next frame can start without any delay on cc::scheduler in
+//              renderer compositors.
+//  gpu: Disable display and browser vsync.
 //  default: Set both flags.
 const char kDisableGpuVsync[]               = "disable-gpu-vsync";
 
 // Turns on GPU logging (debug build only).
 const char kEnableGPUServiceLogging[]       = "enable-gpu-service-logging";
 
 // Turns on calling TRACE for every GL call.
 const char kEnableGPUServiceTracing[]       = "enable-gpu-service-tracing";
 
 // Select which ANGLE backend to use. Options are:
@@ skipping 69 matching lines @@
     kDisableGLDrawingForTests,
     kOverrideUseGLWithOSMesaForTests,
     kUseANGLE,
     kDisableDirectComposition,
     kEnableSwapBuffersWithDamage,
 };
 const int kGLSwitchesCopiedFromGpuProcessHostNumSwitches =
     arraysize(kGLSwitchesCopiedFromGpuProcessHost);
 
 }  // namespace switches