Add SpeechInputBubbleViews::notify_delegate_on_activation_change_, etc.

      Ensure SpeechInputBubbleView continues observing its Widget as it's closed.
Needed so BubbleDelegateView::OnWidgetClosing will close the border widget.

Only notify the SpeechInputBubbleView's delegate when the activation changes through normal user interaction. The SpeechInputBubbleController deletes the SpeechInputBubbleImpl to close it explicitly, and then doesn't expect to be notified on that loss of focus/activation.

BUG=98323,112194
TEST=SpeechInputBubbles behave as expected.

Review URL: http://codereview.chromium.org/9370006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@121192 0039d316-1c4b-4281-b951-d872f2087c98