Add checkdeps presubmit check. Warns on new #includes of dependencies

tools/checkdeps/checkdeps.py

 #!/usr/bin/env python
 # 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.
 
 """Makes sure that files include headers from allowed directories.
 
 Checks DEPS files in the source tree for rules, and applies those rules to
 "#include" commands in source files. Any source file including something not
 permitted by the DEPS files will fail.
@@ skipping 322 matching lines @@
           directory_rules[norm_dir_path] = None
         else:
           ApplyDirectoryRulesAndSkipSubdirs(parent_rules, dir_path)
       return directory_rules[norm_dir_path]
 
     cpp = cpp_checker.CppChecker(self.verbose)
 
     problems = []
     for file_path, include_lines in added_includes:
       # TODO(joi): Make this cover Java as well.
-      if not os.path.splitext(file_path)[1] in cpp.EXTENSIONS:
+      if not cpp.IsCppFile(file_path):
         pass
       rules_for_file = GetDirectoryRules(os.path.dirname(file_path))
       if rules_for_file:
         for line in include_lines:
           is_include, line_status, rule_type = cpp.CheckLine(
               rules_for_file, line, True)
           if rule_type != Rule.ALLOW:
             problems.append((file_path, rule_type, line_status))
     return problems
 
@@ skipping 64 matching lines @@
     for result in results:
       print result
     print "\nFAILED\n"
     return 1
   print "\nSUCCESS\n"
   return 0
 
 
 if '__main__' == __name__:
   sys.exit(main())