Changing the return type of takeScreenshot() (1/n)

Roll back the method, takeScreenshot(), of the UiAutomationConnection
class using by the UiAutomation class due to the return type of the
method, takeScreenshot(), of the AccessibilityService class, isn't
the Bitmap. Besides they also used the different methods of the
SurfaceControl class now.

Bug: 10931661
Test: a11y CTS tests
Change-Id: I7459ebfe77162e51ed3a50c8663e13579a8a67a3