Update BuiltinProvider to provide chrome:// URLs.

Provide common URLs as users start typing "about://" or "chrome://".
Highlight matching input (including "chrome://" for "about:" input).
Support settings sub-pages/paths, e.g. "chrome://settings/foo".
Add BuiltinProviderTest unit test.

Additional hosts will be added when I fix crbug.com/73926.

BUG=55771
TEST=Get chrome:// AutocompleteProvider URLs in the omnibox dropdown.

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=89073

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=89298

Review URL: http://codereview.chromium.org/6995096

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@89356 0039d316-1c4b-4281-b951-d872f2087c98