Build and push chrome.pak for ui_unittests on Android.

build/android/android_commands.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.
 
 """Provides an interface to communicate with the device via the adb command.
 
 Assumes adb binary is currently on system path.
 
 Usage:
@@ skipping 379 matching lines @@
 
   def PushIfNeeded(self, local_path, device_path):
     """Pushes |local_path| to |device_path|.
 
     Works for files and directories. This method skips copying any paths in
     |test_data_paths| that already exist on the device with the same timestamp
     and size.
 
     All pushed files can be removed by calling RemovePushedFiles().
     """
-    assert os.path.exists(local_path)
+    assert os.path.exists(local_path), 'Local path not found %s' % local_path
     self._pushed_files.append(device_path)
 
     # If the path contents are the same, there's nothing to do.
     local_contents = ListHostPathContents(local_path)
     device_contents = self.ListPathContents(device_path)
     # Only compare the size and timestamp if only copying a file because
     # the filename on device can be renamed.
     if os.path.isfile(local_path):
       assert len(local_contents) == 1
       is_equal = local_contents.values() == device_contents.values()
@@ skipping 360 matching lines @@
   options, args = option_parser.parse_args(argv)
 
   commands = AndroidCommands(wait_for_pm=options.wait_for_pm)
   if options.set_asserts != None:
     if commands.SetJavaAssertsEnabled(options.set_asserts):
       commands.Reboot(full_reboot=False)
 
 
 if __name__ == '__main__':
   main(sys.argv)