Revert of Enable DirectComposition by default.

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 gfx {
 
 const char kGLImplementationDesktopName[]     = "desktop";
@@ skipping 48 matching lines @@
 //  osmesa: The OSMesa software renderer.
 const char kUseGL[]                         = "use-gl";
 
 const char kSwiftShaderPath[]               = "swiftshader-path";
 
 // Inform Chrome that a GPU context will not be lost in power saving mode,
 // screen saving mode, etc.  Note that this flag does not ensure that a GPU
 // context will never be lost in any situations, say, a GPU reset.
 const char kGpuNoContextLost[]              = "gpu-no-context-lost";
 
-// Disables the use of DirectComposition to draw to the screen.
-const char kDisableDirectComposition[] = "disable-direct-composition";
+// Turns on the use of DirectComposition to draw to the screen.
+const char kUseDirectComposition[] = "use-direct-composition";
 
 // Indicates whether the dual GPU switching is supported or not.
 const char kSupportsDualGpus[]              = "supports-dual-gpus";
 
 // Flag used for Linux tests: for desktop GL bindings, try to load this GL
 // library first, but fall back to regular library if loading fails.
 const char kTestGLLib[]                     = "test-gl-lib";
 
 // Use hardware gpu, if available, for tests.
 const char kUseGpuInTests[] = "use-gpu-in-tests";
 
 // Enable OpenGL ES 3 APIs without proper service side validation.
 const char kEnableUnsafeES3APIs[] = "enable-unsafe-es3-apis";
 
 // Disables GL drawing operations which produce pixel output. With this
 // the GL output will not be correct but tests will run faster.
 const char kDisableGLDrawingForTests[] = "disable-gl-drawing-for-tests";
 
 // Forces the use of OSMesa instead of hardware gpu.
 const char kOverrideUseGLWithOSMesaForTests[] =
     "override-use-gl-with-osmesa-for-tests";
 
 // Disables specified comma separated GL Extensions if found.
 const char kDisableGLExtensions[] = "disable-gl-extensions";
 
 // This is the list of switches passed from this file that are passed from the
 // GpuProcessHost to the GPU Process. Add your switch to this list if you need
 // to read it in the GPU process, else don't add it.
 const char* kGLSwitchesCopiedFromGpuProcessHost[] = {
-    kDisableGpuVsync,
-    kDisableD3D11,
-    kEnableGPUServiceLogging,
-    kEnableGPUServiceTracing,
-    kEnableUnsafeES3APIs,
-    kGpuNoContextLost,
-    kDisableGLDrawingForTests,
-    kOverrideUseGLWithOSMesaForTests,
-    kUseANGLE,
-    kDisableDirectComposition,
+  kDisableGpuVsync,
+  kDisableD3D11,
+  kEnableGPUServiceLogging,
+  kEnableGPUServiceTracing,
+  kEnableUnsafeES3APIs,
+  kGpuNoContextLost,
+  kDisableGLDrawingForTests,
+  kOverrideUseGLWithOSMesaForTests,
+  kUseANGLE,
+  kUseDirectComposition,
 };
 const int kGLSwitchesCopiedFromGpuProcessHostNumSwitches =
     arraysize(kGLSwitchesCopiedFromGpuProcessHost);
 
 }  // namespace switches