Migrate content/ files to histogram_macros.h includes.

content/renderer/render_thread_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/renderer/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <utility>
 #include <vector>
 
 #include "base/allocator/allocator_extension.h"
 #include "base/command_line.h"
 #include "base/debug/crash_logging.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/discardable_memory_allocator.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/shared_memory.h"
 #include "base/metrics/field_trial.h"
-#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/path_service.h"
 #include "base/run_loop.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/threading/simple_thread.h"
 #include "base/threading/thread_local.h"
 #include "base/threading/thread_restrictions.h"
@@ skipping 2193 matching lines @@
   if (blink::mainThreadIsolate()) {
     blink::mainThreadIsolate()->MemoryPressureNotification(
         v8::MemoryPressureLevel::kCritical);
     blink::MemoryPressureNotificationToWorkerThreadIsolates(
         v8::MemoryPressureLevel::kCritical);
   }
 }
 
 
 }  // namespace content