Adds PRESUBMIT.py check to look for unprefixed string16.

PRESUBMIT.py

 # 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.
 
 """Top-level presubmit script for Chromium.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into gcl.
 """
 
@@ skipping 1008 matching lines @@
   results.extend(_CheckAddedDepsHaveTargetApprovals(input_api, output_api))
   results.extend(
       input_api.canned_checks.CheckChangeHasNoTabs(
           input_api,
           output_api,
           source_file_filter=lambda x: x.LocalPath().endswith('.grd')))
   results.extend(_CheckSpamLogging(input_api, output_api))
   results.extend(_CheckForAnonymousVariables(input_api, output_api))
   results.extend(_CheckCygwinShell(input_api, output_api))
   results.extend(_CheckJavaStyle(input_api, output_api))
+  results.extend(_CheckForString16(input_api, output_api))
 
   if any('PRESUBMIT.py' == f.LocalPath() for f in input_api.AffectedFiles()):
     results.extend(input_api.canned_checks.RunUnitTestsInDirectory(
         input_api, output_api,
         input_api.PresubmitLocalPath(),
         whitelist=[r'^PRESUBMIT_test\.py$']))
   return results
 
 
 def _CheckSubversionConfig(input_api, output_api):
@@ skipping 122 matching lines @@
       bad_macros.extend(_CheckForInvalidOSMacrosInFile(input_api, f))
 
   if not bad_macros:
     return []
 
   return [output_api.PresubmitError(
       'Possibly invalid OS macro[s] found. Please fix your code\n'
       'or add your macro to src/PRESUBMIT.py.', bad_macros)]
 
 
+def _CheckForString16InFile(input_api, f):
+  """Check for string16 without base:: in front."""
+  reg = input_api.re.compile(r'\b(?<!base::)string16\b')
+  use = 'using base::string16;'
+  include = '#include "base/strings/string16.h"'
+  results = []
+  for lnum, line in f.ChangedContents():
+    if reg.search(line) and not include in line and not use in f.NewContents():
+      results.append('    %s:%d' % (f.LocalPath(), lnum))
+  return results
+
+
+def _CheckForString16(input_api, output_api):
+  file_filter = lambda f: input_api.FilterSourceFile(f,
+      white_list=(r'^chrome[\\\/]browser[\\\/]', ),
+      black_list=(_EXCLUDED_PATHS + _TEST_CODE_EXCLUDED_PATHS +
+                  input_api.DEFAULT_BLACK_LIST))
+
+  unprefixed = []
+  for f in input_api.AffectedFiles(file_filter=file_filter):
+    unprefixed.extend(_CheckForString16InFile(input_api, f))
+
+  if not unprefixed:
+    return []
+
+  return [output_api.PresubmitPromptWarning(
+      'string16 should be prefixed with base:: namespace.', unprefixed)]
+
+
 def CheckChangeOnUpload(input_api, output_api):
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   return results
 
 
 def CheckChangeOnCommit(input_api, output_api):
   results = []
   results.extend(_CommonChecks(input_api, output_api))
   # TODO(thestig) temporarily disabled, doesn't work in third_party/
@@ skipping 65 matching lines @@
     trybots += ['cros_x86']
 
   # The AOSP bot doesn't build the chrome/ layer, so ignore any changes to it
   # unless they're .gyp(i) files as changes to those files can break the gyp
   # step on that bot.
   if (not all(re.search('^chrome', f) for f in files) or
       any(re.search('\.gypi?$', f) for f in files)):
     trybots += ['android_aosp']
 
   return trybots