Add presubmit scripts to check histograms.xml if bad_message.h changes.

chrome/browser/PRESUBMIT.py

 # 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.
 
 """Presubmit script for Chromium browser code.
 
 This script currently checks HTML/CSS/JS files in resources/ and ui/webui/.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into depot_tools, and see
 http://www.chromium.org/developers/web-development-style-guide for the rules
 checked for here.
 """
 
 
 def CheckChangeOnUpload(input_api, output_api):
   return _CommonChecks(input_api, output_api)
 
 
 def CheckChangeOnCommit(input_api, output_api):
   return _CommonChecks(input_api, output_api)
 
+def _RunHistogramChecks(input_api, output_api, histogram_name):
+  try:
+    # Setup sys.path so that we can call histrogram code
+    import sys
+    original_sys_path = sys.path
+    sys.path = sys.path + [input_api.os_path.join(
+        input_api.change.RepositoryRoot(),
+        'tools', 'metrics', 'histograms')]
+
+    import presubmit_bad_message_reasons
+    return presubmit_bad_message_reasons.PrecheckBadMessage(input_api,
+      output_api, histogram_name)
+  except:
+    return [output_api.PresubmitError('Could not verify histogram!')]
+  finally:
+    sys.path = original_sys_path
+
 
 def _CommonChecks(input_api, output_api):
   """Checks common to both upload and commit."""
   results = []
 
   path = input_api.os_path
   cwd = input_api.PresubmitLocalPath()
   resources = path.join(cwd, 'resources')
   webui = path.join(cwd, 'ui', 'webui')
 
@@ skipping 35 matching lines @@
           _html_css_js_resource(maybe_resource.AbsoluteLocalPath()))
 
     results.extend(resource_checker.ResourceChecker(
         input_api, output_api, file_filter=is_resource).RunChecks())
     results.extend(css_checker.CSSChecker(
         input_api, output_api, file_filter=is_resource).RunChecks())
     results.extend(html_checker.HtmlChecker(
         input_api, output_api, file_filter=is_resource).RunChecks())
     results.extend(js_checker.JSChecker(
         input_api, output_api, file_filter=is_resource).RunChecks())
+    results.extend(_RunHistogramChecks(input_api, output_api,
+      "BadMessageReasonChrome"))
   finally:
     sys.path = old_path
 
   return results