Update from https://crrev.com/317530

gpu/command_buffer/service/gpu_timing.cc

 // Copyright (c) 2015 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/gpu_timing.h"
 
 #include "base/time/time.h"
+#include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_context.h"
 #include "ui/gl/gl_version_info.h"
 
 namespace gpu {
 
 GPUTimer::GPUTimer(GPUTiming* gpu_timing) : gpu_timing_(gpu_timing) {
   DCHECK(gpu_timing_);
   memset(queries_, 0, sizeof(queries_));
   glGenQueriesARB(2, queries_);
 }
 
 GPUTimer::~GPUTimer() {
   glDeleteQueriesARB(2, queries_);
 }
 
 void GPUTimer::Start() {
   // GL_TIMESTAMP and GL_TIMESTAMP_EXT both have the same value.
   glQueryCounter(queries_[0], GL_TIMESTAMP);
-  offset_ = gpu_timing_->CalculateTimerOffset();
 }
 
 void GPUTimer::End() {
   end_requested_ = true;
+  offset_ = gpu_timing_->CalculateTimerOffset();
   glQueryCounter(queries_[1], GL_TIMESTAMP);
 }
 
 bool GPUTimer::IsAvailable() {
   if (!gpu_timing_->IsAvailable() || !end_requested_) {
     return false;
   }
   GLint done = 0;
   glGetQueryObjectivARB(queries_[1], GL_QUERY_RESULT_AVAILABLE, &done);
   return done != 0;
@@ skipping 95 matching lines @@
 void GPUTiming::SetOffsetForTesting(int64 offset, bool cache_it) {
   offset_ = offset;
   offset_valid_ = cache_it;
 }
 
 void GPUTiming::SetTimerTypeForTesting(TimerType type) {
   timer_type_ = type;
 }
 
 }  // namespace gpu