Use better web app icons.
Use better web app icons.

- Accept "link" element of both "icon" and "shortcut icon" type.
  see also:
    http://en.wikipedia.org/wiki/Favicon
    http://dev.w3.org/html5/spec/Overview.html#rel-icon
- Get complete url from icon link's href;

BUG=none
TEST=Create web app shortcut to "Google Reader" and expect to see crispy clear icon rather than the blur favicon.

Review URL: http://codereview.chromium.org/611008

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@39228 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser