Add and start using Checkstyle 5.7

tools/android/checkstyle/checkstyle.py

 # Copyright 2013 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.
 
 """Script that is used by PRESUBMIT.py to run style checks on Java files."""
 
 import os
 import subprocess
 
 
 def RunCheckstyle(input_api, output_api, style_file):
   if not os.path.exists(style_file):
     file_error = ('  Java checkstyle configuration file is missing: '
                   + style_file)
     return [output_api.PresubmitError(file_error)]
 
   # Filter out non-Java files and files that were deleted.
   java_files = [x.LocalPath() for x in input_api.AffectedFiles(False, False)
                 if os.path.splitext(x.LocalPath())[1] == '.java']
   if not java_files:
     return []
 
   # Run checkstyle
   checkstyle_env = os.environ.copy()
   checkstyle_env['JAVA_CMD'] = 'java'
   try:
-    check = subprocess.Popen(['checkstyle', '-c', style_file] + java_files,
+    check = subprocess.Popen(['java', '-cp',
+                              'third_party/checkstyle/checkstyle-5.7-all.jar',
+                              'com.puppycrawl.tools.checkstyle.Main', '-c',
+                              style_file] + java_files,
                              stdout=subprocess.PIPE, env=checkstyle_env)
     stdout, _ = check.communicate()
     if check.returncode == 0:
       return []
   except OSError as e:
     import errno
     if e.errno == errno.ENOENT:
       install_error = ('  checkstyle is not installed. Please run '
                        'build/install-build-deps-android.sh')
       return [output_api.PresubmitPromptWarning(install_error)]
@@ skipping 11 matching lines @@
   if not errors:
     return []
 
   local_path = input_api.PresubmitLocalPath()
   output = []
   for error in errors:
     # Change the full file path to relative path in the output lines
     full_path, end = error.split(':', 1)
     rel_path = os.path.relpath(full_path, local_path)
     output.append('  %s:%s' % (rel_path, end))
-  return [output_api.PresubmitPromptWarning('\n'.join(output))]
+  return [output_api.PresubmitPromptWarning('\n'.join(output))]