CSSParser should return ImmutableStylePropertySets.

The StylePropertySets created by CSSParser were already immutable.
Let this be reflected in the pointer types returned.

This is a backport from WebKit r148399. Patch by Andreas Kling reviewed by Anders Carlsson.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/16020007

git-svn-id: svn://svn.chromium.org/blink/trunk@151127 bbb929c8-8fbe-4397-9dbb-9b2b20218538
2 files changed