1. Added a mechanism to select the cursor ring content if accessibility is
enabled - This is achieved by sending an event to the WebCore thread
(if accessibility is enabled) to select the content of the cursor when
the latter moves. Added code in WebViewCore to select the given node
and notify the UI thread for the selection markup which is delivered
of the accessibility injector which manages sending accessibility
events. This is relevant for adding accessibility to WebView if
JavaScript is not enabled. (If JS is enabled we inject a screenreader
written in JS).
2. Fixed the event delegation to the accessibility injector since it
should be able to consume key events of interest and perform some
action which leads to sending appropriate accessibility event.
In the previous implementation it was possible that the injector
consumes the event but the latter was bubbled up.
3. Added function to scroll the selection into view while moving it
around based on user commands.
Note: This is a part of two project commmit.
Change-Id: Ibb81d0468726efbe3bf6e3add1b19c69e3206638
c93fb656dc