Fix issue with occasionally missing favicons.

Send progress start/finish notifications on pushState and replaceState.

BUG=259700

Review URL: https://chromiumcodereview.appspot.com/21966006

git-svn-id: svn://svn.chromium.org/blink/trunk@155533 bbb929c8-8fbe-4397-9dbb-9b2b20218538