Remove dead flush histograms code.

content/public/test/mock_render_thread.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.
 
 #include "content/public/test/mock_render_thread.h"
 
 #include "base/logging.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
@@ skipping 199 matching lines @@
 void MockRenderThread::IdleHandler() {
 }
 
 int64_t MockRenderThread::GetIdleNotificationDelayInMs() const {
   return 0;
 }
 
 void MockRenderThread::SetIdleNotificationDelayInMs(
     int64_t idle_notification_delay_in_ms) {}
 
-void MockRenderThread::UpdateHistograms(int sequence_number) {
-}
-
 int MockRenderThread::PostTaskToAllWebWorkers(const base::Closure& closure) {
   return 0;
 }
 
 bool MockRenderThread::ResolveProxy(const GURL& url, std::string* proxy_list) {
   return false;
 }
 
 base::WaitableEvent* MockRenderThread::GetShutdownEvent() {
   return NULL;
@@ skipping 85 matching lines @@
 void MockRenderThread::OnCreateWindow(
     const mojom::CreateNewWindowParams& params,
     mojom::CreateNewWindowReply* reply) {
   reply->route_id = new_window_routing_id_;
   reply->main_frame_route_id = new_window_main_frame_routing_id_;
   reply->main_frame_widget_route_id = new_window_main_frame_widget_routing_id_;
   reply->cloned_session_storage_namespace_id = 0;
 }
 
 }  // namespace content