Remove dead flush histograms code.

content/renderer/render_thread_impl.h

 // 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.
 
 #ifndef CONTENT_RENDERER_RENDER_THREAD_IMPL_H_
 #define CONTENT_RENDERER_RENDER_THREAD_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 189 matching lines @@
       ResourceDispatcherDelegate* delegate) override;
   std::unique_ptr<base::SharedMemory> HostAllocateSharedMemoryBuffer(
       size_t buffer_size) override;
   cc::SharedBitmapManager* GetSharedBitmapManager() override;
   void RegisterExtension(v8::Extension* extension) override;
   void ScheduleIdleHandler(int64_t initial_delay_ms) override;
   void IdleHandler() override;
   int64_t GetIdleNotificationDelayInMs() const override;
   void SetIdleNotificationDelayInMs(
       int64_t idle_notification_delay_in_ms) override;
-  void UpdateHistograms(int sequence_number) override;
   int PostTaskToAllWebWorkers(const base::Closure& closure) override;
   bool ResolveProxy(const GURL& url, std::string* proxy_list) override;
   base::WaitableEvent* GetShutdownEvent() override;
 
   // IPC::Listener implementation via ChildThreadImpl:
   void OnAssociatedInterfaceRequest(
       const std::string& name,
       mojo::ScopedInterfaceEndpointHandle handle) override;
 
   // CompositorDependencies implementation.
@@ skipping 527 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(RenderThreadImpl);
 };
 
 #if defined(COMPILER_MSVC)
 #pragma warning(pop)
 #endif
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_THREAD_IMPL_H_