Migrate chrome/browser files to histogram_macros.h includes.

chrome/browser/extensions/api/metrics_private/metrics_apitest.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 <stddef.h>
 
 #include <map>
 
 #include "base/macros.h"
 #include "base/metrics/field_trial.h"
-#include "base/metrics/histogram.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/metrics/statistics_recorder.h"
 #include "base/test/user_action_tester.h"
 #include "chrome/browser/extensions/extension_apitest.h"
 #include "components/variations/variations_associated_data.h"
 
 namespace {
 
 // The tests that are run by this extension are expected to record the following
 // user actions, with the specified counts.  If the tests in test.js are
 // modified, this array may need to be updated.
@@ skipping 116 matching lines @@
   params["b"] = "bb";
   ASSERT_TRUE(variations::AssociateVariationParams(
       "apitestfieldtrial2", "group1", params));
 
   ASSERT_TRUE(RunComponentExtensionTest("metrics")) << message_;
 
   ValidateUserActions(user_action_tester, g_user_actions,
                       arraysize(g_user_actions));
   ValidateHistograms(g_histograms, arraysize(g_histograms));
 }