browser: Extract AutocompleteProvider from autocomplete.*

This is the first part of splitting autocomplete.* into small pieces, one for
each class.

BUG=94842
R=pkasting@chromium.org
TBR=sky@chromium.org

Review URL: https://chromiumcodereview.appspot.com/10663015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@144107 0039d316-1c4b-4281-b951-d872f2087c98
AutocompleteLog::~AutocompleteLog() {
}

AutocompleteLog::~AutocompleteLog() {
}
