Skip missing translations when generating JSON resources.

tools/grit/grit/format/chrome_messages_json.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.
 
 """Formats as a .json file that can be used to localize Google Chrome
 extensions."""
 
 from json import JSONEncoder
 import re
 import types
 
+from grit import constants
 from grit import util
 from grit.node import message
 
 def Format(root, lang='en', output_dir='.'):
   """Format the messages as JSON."""
   yield '{\n'
 
   encoder = JSONEncoder();
   format = ('  "%s": {\n'
             '    "message": %s%s\n'
             '  }')
   placeholder_format = ('      "%i": {\n'
                         '        "content": "$%i"\n'
                         '      }')
   first = True
   for child in root.ActiveDescendants():
     if isinstance(child, message.MessageNode):
       id = child.attrs['name']
       if id.startswith('IDR_') or id.startswith('IDS_'):
         id = id[4:]
 
+      translation_missing = child.GetCliques()[0].clique.get(lang) is None;
+      if (child.ShouldFallbackToEnglish() and translation_missing and
+          lang != constants.FAKE_BIDI):
+          # Skip the string if it's not translated. Chrome will fallback
+          # to English automatically.
+          continue
+
       loc_message = encoder.encode(child.ws_at_start + child.Translate(lang) +
                                    child.ws_at_end)
 
       # Replace $n place-holders with $n$ and add an appropriate "placeholders"
       # entry. Note that chrome.i18n.getMessage only supports 9 placeholders:
       # https://developer.chrome.com/extensions/i18n#method-getMessage
       placeholders = ''
       for i in range(1, 10):
         if loc_message.find('$%d' % i) == -1:
           break
         loc_message = loc_message.replace('$%d' % i, '$%d$' % i)
         if placeholders:
           placeholders += ',\n'
         placeholders += placeholder_format % (i, i)
 
       if not first:
         yield ',\n'
       first = False
 
       if placeholders:
         placeholders = ',\n    "placeholders": {\n%s\n    }' % placeholders
       yield format % (id, loc_message, placeholders)
 
   yield '\n}\n'