Load the GL_KHR_debug entry points and log messages they produce.

gpu/command_buffer/service/gpu_preferences.h

Index: gpu/command_buffer/service/gpu_preferences.h
diff --git a/gpu/command_buffer/service/gpu_preferences.h b/gpu/command_buffer/service/gpu_preferences.h
index aeab4f27a9e9f3078fb08006a98b156fef178aa6..284c5d7b4fc6705ee60160526bcdf2ea4aea2774 100644
--- a/gpu/command_buffer/service/gpu_preferences.h
+++ b/gpu/command_buffer/service/gpu_preferences.h
@@ -95,6 +95,9 @@ struct GPU_EXPORT GpuPreferences {
   // Enable GPU service logging.
   bool enable_gpu_service_logging_gpu = false;
 
+  // Enable logging of GPU driver debug messages.
+  bool enable_gpu_driver_debug_logging = false;
+
   // Turn off gpu program caching
   bool disable_gpu_program_cache = false;