Route D3D VSync signal to Compositor

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 114 matching lines @@
     kDisableGLDrawingForTests,
     kOverrideUseGLWithOSMesaForTests,
     kUseANGLE,
     kDisableDirectComposition,
     kEnableSwapBuffersWithDamage,
 };
 const int kGLSwitchesCopiedFromGpuProcessHostNumSwitches =
     arraysize(kGLSwitchesCopiedFromGpuProcessHost);
 
 }  // namespace switches
+
+namespace features {
+
+#if defined(OS_WIN)
+// Wait for D3D VSync signals in GPU process (as opposed to delay based VSync
+// generated in Browser process based on VSync parameters).
+const base::Feature kD3DVsync{"D3DVsync", base::FEATURE_DISABLED_BY_DEFAULT};
+#endif  // defined(OS_WIN)
+
+}  // namespace features