Remove deprecated calls to 'v8::String::New' from various files.

BUG=324225
R=haraken@chromium.org, jochen@chromium.org

Review URL: https://codereview.chromium.org/95323002

git-svn-id: svn://svn.chromium.org/blink/trunk@162876 bbb929c8-8fbe-4397-9dbb-9b2b20218538