Add threads stack dumping feature (through SIGUSR1) to test_runner.py.

build/android/test_runner.py

 #!/usr/bin/env python
 #
 # 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.
 
 """Runs all types of tests from one unified interface."""
 
 import collections
 import logging
 import optparse
 import os
 import shutil
+import signal
 import sys
+import threading
+import traceback
 
 from pylib import android_commands
 from pylib import constants
 from pylib import forwarder
 from pylib import ports
 from pylib.base import base_test_result
 from pylib.base import test_dispatcher
 from pylib.gtest import gtest_config
 from pylib.gtest import setup as gtest_setup
 from pylib.gtest import test_options as gtest_test_options
@@ skipping 761 matching lines @@
     'monkey': CommandFunctionTuple(
         AddMonkeyTestOptions, RunTestsCommand),
     'perf': CommandFunctionTuple(
         AddPerfTestOptions, RunTestsCommand),
     'linker': CommandFunctionTuple(
         AddLinkerTestOptions, RunTestsCommand),
     'help': CommandFunctionTuple(lambda option_parser: None, HelpCommand)
     }
 
 
+def DumpThreadStacks(signal, frame):
+  thread_names_map = dict(
+      [(thread.ident, thread.name) for thread in threading.enumerate()])
+  lines = []
+  for thread_id, stack in sys._current_frames().items():
+    lines.append(
+        '\n# Thread: %s (%d)' % (
+            thread_names_map.get(thread_id, ''), thread_id))
+    for filename, lineno, name, line in traceback.extract_stack(stack):
+      lines.append('File: "%s", line %d, in %s' % (filename, lineno, name))
+      if line:
+        lines.append('  %s' % (line.strip()))
+    print '\n'.join(lines)
+
+
 def main(argv):
+  signal.signal(signal.SIGUSR1, DumpThreadStacks)
   option_parser = command_option_parser.CommandOptionParser(
       commands_dict=VALID_COMMANDS)
   return command_option_parser.ParseAndExecute(option_parser)
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))