Add libpeerconnection pdb to the symbol archive.

chrome/tools/build/win/FILES.cfg

 # -*- python -*-
 # ex: set syntax=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.
 
 # This is a buildbot configuration file containing a tagged list of files
 # processed by the stage/archive scripts. The known tags are:
 #
@@ skipping 654 matching lines @@
     'filename': 'libEGL.dll.pdb',
     'buildtype': ['dev', 'official'],
     'archive': 'chrome-win32-syms.zip',
   },
   {
     'filename': 'libGLESv2.dll.pdb',
     'buildtype': ['dev', 'official'],
     'archive': 'chrome-win32-syms.zip',
   },
   {
+    'filename': 'libpeerconnection.dll.pdb',
+    'buildtype': ['dev', 'official'],
+    'archive': 'chrome-win32-syms.zip',
+    'optional': ['dev', 'official'],
+  },
+  {
     'filename': 'mini_installer.exe.pdb',
     'buildtype': ['dev', 'official'],
     'archive': 'chrome-win32-syms.zip',
   },
   {
     'filename': 'nacl64.exe.pdb',
     'arch': ['32bit'],
     'buildtype': ['dev', 'official'],
     'archive': 'chrome-win32-syms.zip',
   },
@@ skipping 43 matching lines @@
     'arch': ['32bit'],
     'buildtype': ['official'],
     'archive': 'chrome-win32-nacl-irt-syms.zip',
   },
   {
     'filename': 'nacl_irt_x86_64.nexe.debug',
     'buildtype': ['official'],
     'archive': 'chrome-win32-nacl-irt-syms.zip',
   },
 ]