Uses SF callback windows for the A11yWindowInfo [1/n]

1. Implements AccessibilityWindowsPopulator class including the
new accessibilityWindow class generated by the inputWindowHandle
from the surface flinger.

2. Replaces the windowState by the accessibilityWindow used in the
AccessibiltyController class for computing the changed windows
reported to the A11y framework.

3. The embedded hiarerchy windows would be reported to A11y framework
due to they are reported from the surface fligner. This will make
the traversal function is broken when the Auotfill features is using
talkback. We find out the embedded hiarerchy windows by its window
token and don't add them into the A11y windows list.

4. Removes the modal windows calculation of the unAccountedSpace
including the task fragment due to we intersec the region between
the frame and touch region for all windows.

5. When reported windows counts from the surface flinger changed,
calling the accessibilty controller class to compute the changed
windows and send the results to the A11y framework immediately.
This can avoid the CTS failure with no corresponding window found
when the activity is launched due to the timing issue between the
callbacks for computing changed windows from the WM and the
callback for changed windows from the surface flinger.

Bug: 191736824
Test: a11y CTS & unit tests
Test: Manual testing including the A11y services
Change-Id: I94d7ed4fbc5abab2252ddccae55678014ac9e600