Notify the client of a document access even if document.write is used.

Modal dialogs can usually delay the notification from reaching the client.
notifyIfInitialDocumentAccessed is used to skip the timer if a dialog
is shown (via PageGroupLoadDeferrer), but it shouldn't care whether the
FrameLoader is still in the initial empty document state.

BUG=322959
TEST=See bug for repro steps.

Review URL: https://codereview.chromium.org/86413004

git-svn-id: svn://svn.chromium.org/blink/trunk@162673 bbb929c8-8fbe-4397-9dbb-9b2b20218538