Add exception handling in get_drt.py

tools/get_drt.py

 #!/usr/bin/env python
 #
 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # Gets or updates a DumpRenderTree (a nearly headless build of chrome). This is
 # used for running browser tests of client applications.
 
 import optparse
@@ skipping 144 matching lines @@
     temp_zip = os.path.join(temp_dir, 'drt.zip')
     temp_zip_url = 'file://' + temp_zip
     # It's nice to show download progress
     gsutil_visible('cp', latest, temp_zip_url)
 
     if platform.system() != 'Windows':
       # The Python zip utility does not preserve executable permissions, but
       # this does not seem to be a problem for Windows, which does not have a
       # built in zip utility. :-/
       result, out = execute_command('unzip', temp_zip, '-d', temp_dir)
+      if result != 0:
+        raise Exception('Execution of "unzip %s -d %s" failed: %s' %
+                        (temp_zip, temp_dir, str(out)))
       unzipped_dir = temp_dir + '/' + os.path.basename(latest)[:-4] #Remove .zip
     else:
       z = zipfile.ZipFile(temp_zip)
       z.extractall(temp_dir)
       # -4 = remove .zip for dir name
       unzipped_dir = os.path.join(temp_dir, os.path.basename(latest)[:-4])
       z.close()
     shutil.move(unzipped_dir, directory)
   finally:
     shutil.rmtree(temp_dir)
@@ skipping 16 matching lines @@
 
   if args.dartium:
     get_latest('Dartium', DARTIUM_DIR, DARTIUM_VERSION,
                DARTIUM_LATEST_PATTERN, DARTIUM_PERMANENT_PREFIX)
   else:
     get_latest('DumpRenderTree', DRT_DIR, DRT_VERSION,
                DRT_LATEST_PATTERN, DRT_PERMANENT_PREFIX)
 
 if __name__ == '__main__':
   sys.exit(main())