Add and start using Checkstyle 5.7

tools/android/checkstyle/checkstyle.py

Index: tools/android/checkstyle/checkstyle.py
diff --git a/tools/android/checkstyle/checkstyle.py b/tools/android/checkstyle/checkstyle.py
index c47fbee45c156703dbad8d41c4fff65fc16a5813..33cd33df27ac0f6ab3acc15e9b297135b689734f 100644
--- a/tools/android/checkstyle/checkstyle.py
+++ b/tools/android/checkstyle/checkstyle.py
@@ -24,7 +24,10 @@ def RunCheckstyle(input_api, output_api, style_file):
   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:
@@ -56,4 +59,4 @@ def RunCheckstyle(input_api, output_api, style_file):
     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))]