gl: Disable SGI_video_sync by default.

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 31030c4e8e4f6434e3213a26db6aad0afe424c65..55a19dcadf060b75359efc29727a8ef279cd32c9 100644
--- a/ui/gl/gl_switches.cc
+++ b/ui/gl/gl_switches.cc
@@ -82,6 +82,10 @@ const char kUseGpuInTests[] = "use-gpu-in-tests";
 // Enable OpenGL ES 3 APIs without proper service side validation.
 const char kEnableUnsafeES3APIs[] = "enable-unsafe-es3-apis";
 
+// Enable use of the SGI_video_sync extension, which can have
+// driver/sandbox/window manager compatibility issues.
+const char kEnableSgiVideoSync[] = "enable-sgi-video-sync";

[piman, 2016/08/25 00:22:52]

Please add this to kGLSwitchesCopiedFromGpuProcessHost below, otherwise the flag
will not make it to the GPU process.

[brianderson, 2016/08/25 01:46:05]

Done.

+
 // 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";