gl: Disable SGI_video_sync 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 gl {
 
 const char kGLImplementationDesktopName[]     = "desktop";
@@ skipping 64 matching lines @@
 // 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";
 
+// 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";
 
 // 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";
@@ skipping 11 matching lines @@
     kDisableGLDrawingForTests,
     kOverrideUseGLWithOSMesaForTests,
     kUseANGLE,
     kDisableDirectComposition,
 };
 const int kGLSwitchesCopiedFromGpuProcessHostNumSwitches =
     arraysize(kGLSwitchesCopiedFromGpuProcessHost);
 
 }  // namespace switches