[Print Preview]: Added code to support pdf fit to page functionality.

BUG=85132
TEST=none


Review URL: https://chromiumcodereview.appspot.com/10083060

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@137498 0039d316-1c4b-4281-b951-d872f2087c98
  ~PrintPreviewRequestIdMapWithLock() {}

  ~PrintPreviewRequestIdMapWithLock() {}
