Cache strings that come directly from WebLocalizedString

     Cache strings that come directly from WebLocalizedString

         Reviewed by Steve.

         * WebLocalizableStrings.cpp:
         (copyLocalizedStringFromBundle): This used to be WebLocalizedString,
         but is now just a static helper function.
         (findCachedStringInMap): Added static helper.
         (findCachedString): Refactored and cleaned up code from
         WebLocalizedLPCTSTR.
         (cacheString): Ditto.
         (WebLocalizedString): Rewrote to use the new helper functions.
         (WebLocalizedLPCTSTR): Changed to use the new helper functions.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@27443 268f45cc-cd09-0410-ab3c-d52691b4dbfc