gpu: Prefer GL_ARB_sync over GL_NV_fence.

ui/gl/gl_fence.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/gl/gl_fence.h"
 
 #include "base/compiler_specific.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_context.h"
 
@@ skipping 111 matching lines @@
   EGLDisplay display_;
 };
 #endif // !OS_MACOSX
 
 // static
 gfx::GLFence* CreateFence(bool flush) {
 #if !defined(OS_MACOSX)
   if (gfx::g_driver_egl.ext.b_EGL_KHR_fence_sync)
     return new EGLFenceSync(flush);
 #endif
+  // Prefer ARB_sync which supports server-side wait.
+  if (gfx::g_driver_gl.ext.b_GL_ARB_sync)
+    return new GLFenceARBSync(flush);
   if (gfx::g_driver_gl.ext.b_GL_NV_fence)
     return new GLFenceNVFence(flush);
-  if (gfx::g_driver_gl.ext.b_GL_ARB_sync)
-    return new GLFenceARBSync(flush);
   return NULL;
 }
 
 }  // namespace
 
 namespace gfx {
 
 GLFence::GLFence() {
 }
 
 GLFence::~GLFence() {
 }
 
 GLFence* GLFence::Create() {
   return CreateFence(true);
 }
 
 GLFence* GLFence::CreateWithoutFlush() {
   return CreateFence(false);
 }
 
 }  // namespace gfx