Moved skip...() functions from ContentSecurityPolicy.cpp into ParsingUtilities.h

The purpose is to make them generically available for parsing algorithms.
The functions were required as part of the https://codereview.chromium.org/23861003/ CL review.
Adding templates was required so that these function could work with multiple character types and specifically UChar and LChar.

BUG=284722

Review URL: https://chromiumcodereview.appspot.com/23464104

git-svn-id: svn://svn.chromium.org/blink/trunk@158107 bbb929c8-8fbe-4397-9dbb-9b2b20218538