[Extension API Extern Generation] Fix a few bugs in extern generation

tools/json_schema_compiler/code.py

 # 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.
 
 class Code(object):
   """A convenience object for constructing code.
 
   Logically each object should be a block of code. All methods except |Render|
   and |IsEmpty| return self.
   """
@@ skipping 114 matching lines @@
       if last_space != -1:
         line = comment[0:last_space]
         comment = comment[last_space + 1:]
       else:
         line = comment[0:max_len]
         comment = comment[max_len:]
       return line, comment
 
     # First line has the full maximum length.
     if not new_line and self._code:
-      max_len = self._comment_length - len(self._code[-1].value) - 1
+      max_len = self._comment_length - len(self._code[-1].value)
     else:
       max_len = (self._comment_length - len(''.join(self._line_prefixes)) -
                  len(comment_prefix))
     line, comment = trim_comment(comment, max_len)
     self.Append(comment_prefix + line, substitute=False, new_line=new_line)
 
     # Any subsequent lines be subject to the wrap indent.
     max_len = (self._comment_length - len(''.join(self._line_prefixes)) -
                len(comment_prefix) - wrap_indent)
     while len(comment):
@@ skipping 29 matching lines @@
     """
     return '\n'.join([l.value for l in self._code])
 
 
 class Line(object):
   """A line of code.
   """
   def __init__(self, value, substitute=True):
     self.value = value
     self.substitute = substitute