Enable DirectComposition by default.

ui/gl/gl_surface_egl.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_surface_egl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "base/command_line.h"
@@ skipping 374 matching lines @@
   g_egl_window_fixed_size_supported =
       HasEGLExtension("EGL_ANGLE_window_fixed_size");
   g_egl_surface_orientation_supported =
       HasEGLExtension("EGL_ANGLE_surface_orientation");
 
   // Need EGL_ANGLE_flexible_surface_compatibility to allow surfaces with and
   // without alpha to be bound to the same context.
   g_use_direct_composition =
       HasEGLExtension("EGL_ANGLE_direct_composition") &&
       HasEGLExtension("EGL_ANGLE_flexible_surface_compatibility") &&
-      base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kUseDirectComposition);
+      !base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableDirectComposition);
 
   // TODO(oetuaho@nvidia.com): Surfaceless is disabled on Android as a temporary
   // workaround, since code written for Android WebView takes different paths
   // based on whether GL surface objects have underlying EGL surface handles,
   // conflicting with the use of surfaceless. See https://crbug.com/382349
 #if defined(OS_ANDROID)
   DCHECK(!g_egl_surfaceless_context_supported);
 #else
   // Check if SurfacelessEGL is supported.
   g_egl_surfaceless_context_supported =
@@ skipping 617 matching lines @@
 }
 
 void* SurfacelessEGL::GetShareHandle() {
   return NULL;
 }
 
 SurfacelessEGL::~SurfacelessEGL() {
 }
 
 }  // namespace gfx