GitLab

This CL introduces an interface that will be used to access all of chrome/ API.
It is implemented by the FaviconTabHelper, and allows moving the
GetFaviconService() method out of the FaviconHandler.

BUG=359095

Review URL: https://codereview.chromium.org/228783002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@262960 0039d316-1c4b-4281-b951-d872f2087c98