Load the GL_KHR_debug entry points and log messages they produce.

gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc

 // Copyright (c) 2016 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 "gpu/command_buffer/service/gles2_cmd_decoder_passthrough.h"
 
 #include "gpu/command_buffer/service/feature_info.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "ui/gl/gl_version_info.h"
 
@@ skipping 160 matching lines @@
 
   mailbox_manager_ = group_->mailbox_manager();
 
   // Query information about the texture units
   GLint num_texture_units = 0;
   glGetIntegerv(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS, &num_texture_units);
 
   active_texture_unit_ = 0;
   bound_textures_.resize(num_texture_units, 0);
 
+  if (group_->gpu_preferences().enable_gpu_driver_debug_logging &&
+      feature_info_->feature_flags().khr_debug) {
+    InitializeGLDebugLogging();
+  }
+
   set_initialized();
   return true;
 }
 
 void GLES2DecoderPassthroughImpl::Destroy(bool have_context) {
   image_manager_.reset();
 
   DeleteServiceObjects(
       &framebuffer_id_map_, have_context,
       [](GLuint framebuffer) { glDeleteFramebuffersEXT(1, &framebuffer); });
@@ skipping 336 matching lines @@
   }, /* NOLINT */
 
 const GLES2DecoderPassthroughImpl::CommandInfo
     GLES2DecoderPassthroughImpl::command_info[] = {
         GLES2_COMMAND_LIST(GLES2_CMD_OP)};
 
 #undef GLES2_CMD_OP
 
 }  // namespace gles2
 }  // namespace gpu