Migrate content/ files to histogram_macros.h includes.

content/renderer/media/webrtc_uma_histograms.cc

 // Copyright 2014 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/renderer/media/webrtc_uma_histograms.h"
 
-#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_macros.h"
 
 namespace content {
 
 void LogUserMediaRequestWithNoResult(MediaStreamRequestState state) {
   UMA_HISTOGRAM_ENUMERATION("WebRTC.UserMediaRequest.NoResultState",
                             state,
                             NUM_MEDIA_STREAM_REQUEST_WITH_NO_RESULT);
 }
 
 void LogUserMediaRequestResult(MediaStreamRequestResult result) {
@@ skipping 44 matching lines @@
     LogUsage(api_name);
   }
 }
 
 void PerSessionWebRTCAPIMetrics::ResetUsage() {
   for (bool& has_used_api : has_used_api_)
     has_used_api = false;
 }
 
 }  // namespace content