Migrate content/ files to histogram_macros.h includes.

content/common/gpu/client/command_buffer_metrics.cc

 // Copyright 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 "content/common/gpu/client/command_buffer_metrics.h"
 
-#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_macros.h"
 
 namespace content {
 namespace command_buffer_metrics {
 
 namespace {
 
 enum CommandBufferContextLostReason {
   // Don't add new values here.
   CONTEXT_INIT_FAILED,
   CONTEXT_LOST_GPU_CHANNEL_ERROR,
@@ skipping 155 matching lines @@
 void UmaRecordContextLost(ContextType type,
                           gpu::error::Error error,
                           gpu::error::ContextLostReason reason) {
   CommandBufferContextLostReason converted_reason =
       GetContextLostReason(error, reason);
   RecordContextLost(type, converted_reason);
 }
 
 }  // namespace command_buffer_metrics
 }  // namespace content