gl: Disable SGI_video_sync by default.

ui/gfx/vsync_provider.cc

Index: ui/gfx/vsync_provider.cc
diff --git a/ui/gfx/image/image_skia_source.cc b/ui/gfx/vsync_provider.cc
similarity index 55%
copy from ui/gfx/image/image_skia_source.cc
copy to ui/gfx/vsync_provider.cc
index 53bc4271ca78ecbb384aa42f73e81bcf8e11decf..a7ee070e41bf9b726220acef50c12126c40fbb81 100644
--- a/ui/gfx/image/image_skia_source.cc
+++ b/ui/gfx/vsync_provider.cc
@@ -2,12 +2,13 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "ui/gfx/image/image_skia_source.h"
+#include "ui/gfx/vsync_provider.h"
 
 namespace gfx {
 
-ImageSkiaSource::~ImageSkiaSource() {}
-
-bool ImageSkiaSource::HasRepresentationAtAllScales() const { return false; }
+void FixedVSyncProvider::GetVSyncParameters(
+    const UpdateVSyncCallback& callback) {
+  callback.Run(timebase_, interval_);
+}
 
 }  // namespace gfx