CrOS: Log violations of GLX_OML_sync_control spec.

ui/gl/vsync_provider.cc

 // Copyright (c) 2013 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 "ui/gl/vsync_provider.h"
 
 #include <math.h>
 
 #include "base/logging.h"
 #include "base/time.h"
@@ skipping 47 matching lines @@
   int64 system_time;
   int64 media_stream_counter;
   int64 swap_buffer_counter;
   if (!GetSyncValues(&system_time,
                      &media_stream_counter,
                      &swap_buffer_counter))
     return;
 
   // Both Intel and Mali drivers will return TRUE for GetSyncValues
   // but a value of 0 for MSC if they cannot access the CRTC data structure
-  // associated with the surfrace.
-  if (media_stream_counter == 0)
+  // associated with the surfrace. crbug.com/231945
+  if (media_stream_counter == 0) {
+    LOG(ERROR) << "glXGetSyncValuesOML should not return TRUE with a "
+               << "media stream counter of 0.";
     return;
+  }
 
   struct timespec real_time;
   struct timespec monotonic_time;
   clock_gettime(CLOCK_REALTIME, &real_time);
   clock_gettime(CLOCK_MONOTONIC, &monotonic_time);
 
   int64 real_time_in_microseconds =
     real_time.tv_sec * base::Time::kMicrosecondsPerSecond +
     real_time.tv_nsec / base::Time::kNanosecondsPerMicrosecond;
   int64 monotonic_time_in_microseconds =
@@ skipping 68 matching lines @@
     }
   }
 
   last_timebase_ = timebase;
   last_media_stream_counter_ = media_stream_counter;
   callback.Run(timebase, last_good_interval_);
 #endif  // defined(OS_LINUX)
 }
 
 }  // namespace gfx