Fix unit test failures caused by bad ParamTraits for WebString.
Fix unit test failures caused by bad ParamTraits for WebString.

TBR=agl

Review URL: http://codereview.chromium.org/57067

git-svn-id: http://src.chromium.org/svn/trunk/src@12884 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 8a76b0b5f86d63e8dc5e0b0ad043423c1ffd59d3
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser