[iOS] Adds a version check function for iOS 7.

BUG=None
TEST=None

Review URL: https://chromiumcodereview.appspot.com/18171002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@209314 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed