Added deobfuscation script for ProGuarded stacktraces

BUG=625704

Review-Url: https://codereview.chromium.org/2126353002
Cr-Commit-Position: refs/heads/master@{#404476}

build/android/stacktrace/java_deobfuscate.py

+#!/usr/bin/env python
+# Copyright 2016 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.
+
+"""A tool to deobfuscate Java stack traces.
+
+Utility wrapper around ReTrace to deobfuscate stack traces that have been
+mangled by ProGuard. Takes stack traces from stdin (eg. adb logcat |
+java_deobfuscate.py proguard.mapping) and files.
+"""
+
+# Can just run:
+# java -jar third_party/proguard/lib/retrace.jar -regex \
+# "(?:.*?\bat\s+%c\.%m\s*\(%s(?::%l)?\)\s*)|(?:(?:.*?[:\"]\s+)?%c(?::.*)?)" \
+# ~/mapping
+# in terminal to achieve same effect as this tool.
+
+import argparse
+import os
+import subprocess
+import sys
+
+_THIRD_PARTY_DIR = os.path.abspath(os.path.join(os.path.dirname(__file__),
+                                                os.pardir, os.pardir, os.pardir,
+                                                'third_party'))
+sys.path.append(os.path.join(_THIRD_PARTY_DIR, 'catapult', 'devil'))
+from devil.utils import cmd_helper
+
+
+# This regex is taken from
+# http://proguard.sourceforge.net/manual/retrace/usage.html.
+_LINE_PARSE_REGEX = (
+    r'(?:.*?\bat\s+%c\.%m\s*\(%s(?::%l)?\)\s*)|(?:(?:.*?[:"]\s+)?%c(?::.*)?)')
+
+
+def main():
+  parser = argparse.ArgumentParser(description=(__doc__))
+  parser.add_argument(
+      'mapping_file',
+      help='ProGuard mapping file from build which the stacktrace is from.')
+  parser.add_argument(
+      '--stacktrace',
+      help='Stacktrace file to be deobfuscated.')
+  args = parser.parse_args()
+
+  retrace_path = os.path.join(_THIRD_PARTY_DIR, 'proguard',
+                              'lib', 'retrace.jar')
+
+  base_args = ['java', '-jar', retrace_path, '-regex', _LINE_PARSE_REGEX,
+               args.mapping_file]
+  if args.stacktrace:
+    subprocess.call(base_args + [args.stacktrace])
+  else:
+    for line in cmd_helper.IterCmdOutputLines(base_args):
+      print line
+
+
+if __name__ == '__main__':
+  main()