Text selection should happen on Disabled and Readonly elements when do
long press on those elements in Android for allowing user to Copy.

HitTest is coming as the layered parent node, so text selection is
not happening. This change takes care of processing text selection in
case of disabled/readonly elements.

Review URL: https://codereview.chromium.org/309553007

git-svn-id: svn://svn.chromium.org/blink/trunk@184746 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Cache the parent of an AXObject rather than computing it each time.

BUG=427947

Review URL: https://codereview.chromium.org/687553004

git-svn-id: svn://svn.chromium.org/blink/trunk@184747 bbb929c8-8fbe-4397-9dbb-9b2b20218538