Route D3D VSync signal to Compositor

ui/gl/gl_switches.cc

Index: ui/gl/gl_switches.cc
diff --git a/ui/gl/gl_switches.cc b/ui/gl/gl_switches.cc
index 3fabe5c7432a56189ad7c01048712d463da76bea..9271f5bf1f057d307bc15eb62f382b82a354f5b3 100644
--- a/ui/gl/gl_switches.cc
+++ b/ui/gl/gl_switches.cc
@@ -134,3 +134,13 @@ 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