Removing itemCount, fromIndex and toIndex from

AccessibilityEvent.TYPE_VIEW_SCROLLED sent by PagedView.
This causes an additional reduntant voice message on scroll (see the
bug).

Also, setting these attributes violate rules set here:
http://developer.android.com/reference/android/view/accessibility/AccessibilityEvent.html
i.e. that these fields should be set only for descendants of
AdapterView.

Note that we can't just stop sending TYPE_VIEW_SCROLLED, because in this
case, accessibility focus won't be set after scrolling.

Bug: 21304383
Change-Id: I84f8e064d8209c0e09d6827551e00c9913829b57