Make javac and jar a single build action

build/android/gyp/util/build_utils.py

 # 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.
 
 import contextlib
 import fnmatch
 import json
 import os
 import pipes
 import shlex
@@ skipping 23 matching lines @@
     os.makedirs(dir_path)
   except OSError:
     pass
 
 
 def DeleteDirectory(dir_path):
   if os.path.exists(dir_path):
     shutil.rmtree(dir_path)
 
 
-def Touch(path):
+def Touch(path, fail_if_missing=False):
+  if fail_if_missing and not os.path.exists(path):
+    raise Exception(path + ' doesn\'t exist.')
+
   MakeDirectory(os.path.dirname(path))
   with open(path, 'a'):
     os.utime(path, None)
 
 
 def FindInDirectory(directory, filename_filter):
   files = []
   for root, _dirnames, filenames in os.walk(directory):
     matched_files = fnmatch.filter(filenames, filename_filter)
     files.extend((os.path.join(root, f) for f in matched_files))
@@ skipping 147 matching lines @@
 
 
 def PrintWarning(message):
   print 'WARNING: ' + message
 
 
 def PrintBigWarning(message):
   print '*****     ' * 8
   PrintWarning(message)
   print '*****     ' * 8