Add PRESUMIT for accessibility_mode_enums values

content/common/PRESUBMIT.py

Index: content/common/PRESUBMIT.py
diff --git a/content/common/PRESUBMIT.py b/content/common/PRESUBMIT.py
new file mode 100644
index 0000000000000000000000000000000000000000..5716b45c1a38ebf49f50520655af5b577c9c9f60
--- /dev/null
+++ b/content/common/PRESUBMIT.py
@@ -0,0 +1,89 @@
+# Copyright 2017 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 content/common."""
+
+import os, re
+
+AX_JS_FILE = 'content/browser/resources/accessibility/accessibility.js'
+AX_MODE_HEADER = 'content/common/accessibility_mode.h'
+
+# Given a full path to c++ header, return an array of the first static
+# constexpr defined. (Note there can be more than one defined in a C++
+# header)
+def GetConstexprFromFile(fullpath):
+  values = []
+  for line in open(fullpath).readlines():
+    # Strip out comments
+    line = re.sub('//.*', '', line)
+
+    # Look for lines of the form "static constexpr <type> NAME "
+    m = re.search('static constexpr [\w]+ ([\w]+)', line)
+    if m:
+      values.append(m.group(1))
+
+  return values
+
+# Given a full path to js file, return the AccessibilityMode consts
+# defined
+def GetAccessibilityModesFromFile(fullpath):
+  values = []
+  inside = False
+  for line in open(fullpath).readlines():
+    # Strip out comments
+    line = re.sub('//.*', '', line)
+
+    # Look for the block of code that defines AccessibilityMode
+    m = re.search('const AccessibilityMode = {', line)
+    if m:
+      inside = True
+      continue
+
+    # Look for a "}" character signifying the end of an enum
+    if line.find('};') >= 0:
+      return values
+
+    if not inside:
+      continue
+
+    m = re.search('([\w]+):', line)
+    if m:
+      values.append(m.group(1))
+      continue
+
+    # getters
+    m = re.search('get ([\w]+)\(\)', line)
+    if m:
+      values.append(m.group(1))
+  return values
+
+# Make sure that the modes defined in the C++ header match those defined in
+# the js file. Note that this doesn't guarantee that the values are the same,
+# but does make sure if we add or remove we can signal to the developer that
+# they should be aware that this dependency exists.
+def CheckModesMatch(input_api, output_api):
+  errs = []
+  repo_root = input_api.change.RepositoryRoot()
+
+  ax_modes_in_header = GetConstexprFromFile(
+    os.path.join(repo_root,AX_MODE_HEADER))
+  ax_modes_in_js = GetAccessibilityModesFromFile(
+    os.path.join(repo_root, AX_JS_FILE))
+
+  for value in ax_modes_in_header:
+    if value not in ax_modes_in_js:
+      errs.append(output_api.PresubmitError(
+          'Found %s in %s, but did not find %s in %s' % (
+              value, AX_MODE_HEADER, value, AX_JS_FILE)))
+  return errs
+
+def CheckChangeOnUpload(input_api, output_api):
+  if AX_MODE_HEADER not in input_api.LocalPaths():
+    return []
+  return CheckModesMatch(input_api, output_api)
+
+def CheckChangeOnCommit(input_api, output_api):
+  if AX_MODE_HEADER not in input_api.LocalPaths():
+    return []
+  return CheckModesMatch(input_api, output_api)