Fix latency tests

ui/gl/gl_surface_glx.cc

 // Copyright (c) 2012 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.
 
 extern "C" {
 #include <X11/Xlib.h>
 }
 
 #include "ui/gl/gl_surface_glx.h"
 
 #include "base/basictypes.h"
+#include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "base/process_util.h"
 #include "third_party/mesa/MesaLib/include/GL/osmesa.h"
 #include "ui/base/x/x11_util.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_implementation.h"
 
 namespace gfx {
@@ skipping 106 matching lines @@
   size_ = size;
   return true;
 }
 
 bool NativeViewGLSurfaceGLX::IsOffscreen() {
   return false;
 }
 
 bool NativeViewGLSurfaceGLX::SwapBuffers() {
   glXSwapBuffers(g_display, window_);
+  // For latency_tests.cc:
+  UNSHIPPED_TRACE_EVENT_INSTANT0("test_gpu", "CompositorSwapBuffersComplete");
   return true;
 }
 
 gfx::Size NativeViewGLSurfaceGLX::GetSize() {
   return size_;
 }
 
 void* NativeViewGLSurfaceGLX::GetHandle() {
   return reinterpret_cast<void*>(window_);
 }
@@ skipping 167 matching lines @@
 
 void* PbufferGLSurfaceGLX::GetConfig() {
   return config_;
 }
 
 PbufferGLSurfaceGLX::~PbufferGLSurfaceGLX() {
   Destroy();
 }
 
 }  // namespace gfx