Use FILES.cfg for Windows symbols on chromium builds.
Use FILES.cfg for Windows symbols on chromium builds.

This allows us to exclude syzygy symbols which are not needed for
non-official builds, and which are just bloating our build archives and
slowing cycle times.

Note, this is only part of the change. A related change for the buildbot
scripts is in another CL.

TEST=Windows symbols archives unchanged for both Chrome and Chromium.

Review URL: https://chromiumcodereview.appspot.com/10007042

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@131161 0039d316-1c4b-4281-b951-d872f2087c98

yitian134/chromium,adobe/chromium,ropik/chromium,yitian134/chromium,yitian134/chromium,yitian134/chromium,ropik/chromium,adobe/chromium,yitian134/chromium,adobe/chromium,adobe/chromium,adobe/chromium,yitian134/chromium,adobe/chromium,yitian134/chromium,ropik/chromium,ropik/chromium,adobe/chromium,ropik/chromium,yitian134/chromium,adobe/chromium,yitian134/chromium,adobe/chromium,yitian134/chromium,adobe/chromium,ropik/chromium,ropik/chromium,adobe/chromium,ropik/chromium,ropik/chromium