Accessibility shortcut on Android TV.

	- Added a Long Press (HOME + DPAD_CENTER) combination
	  as the Accessibility shortcut.

Note: Accessibility Shortcut in TV Settings still needs to be put in.

Test: Manual - Pressed the key combination and watched logs.
Test: Manual - watch -n 1 'adb shell dumpsys window policy | grep mAccess'
		will show the keys pressed at any given time.

Bug: 36572948
Change-Id: I557aabad84b2c02ea195754fa2bd051934e324ee