Migrate content/ files to histogram_macros.h includes.

content/common/child_process_host_impl.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/common/child_process_host_impl.h"
 
 #include <limits>
 
 #include "base/atomic_sequence_num.h"
 #include "base/command_line.h"
 #include "base/files/file_path.h"
 #include "base/hash.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
-#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/numerics/safe_math.h"
 #include "base/path_service.h"
 #include "base/process/process_metrics.h"
 #include "base/rand_util.h"
 #include "base/strings/stringprintf.h"
 #include "base/synchronization/lock.h"
 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
 #include "build/build_config.h"
 #include "content/common/child_process_messages.h"
 #include "content/public/common/child_process_host_delegate.h"
@@ skipping 353 matching lines @@
 }
 
 void ChildProcessHostImpl::OnDeletedGpuMemoryBuffer(
     gfx::GpuMemoryBufferId id,
     const gpu::SyncToken& sync_token) {
   // Note: Nothing to do here as ownership of shared memory backed
   // GpuMemoryBuffers is passed with IPC.
 }
 
 }  // namespace content