Migrate content/ files to histogram_macros.h includes.

content/common/host_discardable_shared_memory_manager.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/common/host_discardable_shared_memory_manager.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/atomic_sequence_num.h"
@@ skipping 15 matching lines @@
 #include "base/trace_event/process_memory_dump.h"
 #include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
 #include "content/common/child_process_host_impl.h"
 #include "content/common/discardable_shared_memory_heap.h"
 #include "content/public/common/child_process_host.h"
 
 #if defined(OS_LINUX)
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
-#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_macros.h"
 #endif
 
 namespace content {
 namespace {
 
 class DiscardableMemoryImpl : public base::DiscardableMemory {
  public:
   DiscardableMemoryImpl(
       std::unique_ptr<base::DiscardableSharedMemory> shared_memory,
       const base::Closure& deleted_callback)
@@ skipping 502 matching lines @@
     return;
 
   enforce_memory_policy_pending_ = true;
   DCHECK(enforce_memory_policy_task_runner_);
   enforce_memory_policy_task_runner_->PostDelayedTask(
       FROM_HERE, enforce_memory_policy_callback_,
       base::TimeDelta::FromMilliseconds(kEnforceMemoryPolicyDelayMs));
 }
 
 }  // namespace content