Send vsync timebase updates to the browser compositor

ui/gl/gl_surface_glx.cc

Index: ui/gl/gl_surface_glx.cc
diff --git a/ui/gl/gl_surface_glx.cc b/ui/gl/gl_surface_glx.cc
index 8428cfcf1ae940d4c68060a93c2d8c4a83850ac7..b8f45a535ef8da05ab319b4c762507cdc346951d 100644
--- a/ui/gl/gl_surface_glx.cc
+++ b/ui/gl/gl_surface_glx.cc
@@ -36,6 +36,7 @@ class ScopedPtrXFree {
 Display* g_display;
 const char* g_glx_extensions = NULL;
 bool g_glx_create_context_robustness_supported = false;
+bool g_glx_oml_sync_control_supported = false;
 
 }  // namespace
 
@@ -67,6 +68,9 @@ bool GLSurfaceGLX::InitializeOneOff() {
   g_glx_create_context_robustness_supported =
       HasGLXExtension("GLX_ARB_create_context_robustness");
 
+  g_glx_oml_sync_control_supported =
+      HasGLXExtension("GLX_OML_sync_control");
+
   initialized = true;
   return true;
 }
@@ -86,6 +90,11 @@ bool GLSurfaceGLX::IsCreateContextRobustnessSupported() {
   return g_glx_create_context_robustness_supported;
 }
 
+// static
+bool GLSurfaceGLX::IsOMLSyncControlSupported() {
+  return g_glx_oml_sync_control_supported;
+}
+
 void* GLSurfaceGLX::GetDisplay() {
   return g_display;
 }
@@ -216,6 +225,17 @@ bool NativeViewGLSurfaceGLX::PostSubBuffer(
   return true;
 }
 
+bool NativeViewGLSurfaceGLX::GetSyncValues(int64_t* systemTime,
+                                           int64_t* mediaStreamCounter,
+                                           int64_t* swapBufferCounter) {
+  if (g_glx_oml_sync_control_supported) {
+    return glXGetSyncValuesOML(g_display, window_, systemTime,
+                               mediaStreamCounter, swapBufferCounter);
+  }
+
+  return false;
+}
+
 NativeViewGLSurfaceGLX::NativeViewGLSurfaceGLX()
   : window_(0),
     config_(NULL) {