Integrate OnReceiveContentListener in View.onDragEvent

OnReceiveContentListener was already integrated with drag-and-drop
in TextView. The change extends support to all subclasses of View.

If an OnReceiveContentListener is set on the view, the default
implementation of View.onDragEvent will now return true for an
ACTION_DRAG_STARTED event and will call
View.performReceiveContent for an ACTION_DROP event.

Bug: 182617122
Test: atest CtsWindowManagerDeviceTestCases:CrossAppDragAndDropTests
Test: atest CtsViewTestCases:ViewOnReceiveContentTest
Test: atest CtsWidgetTestCases:TextViewOnReceiveContentTest
Test: Manually using ReceiveContentDemo
Change-Id: I98fb703220ebd1953b20dcab60d22847cc5000d8