Check default focus highlight for ImageView.

This commit specially checks isDefaultFocusHighlightNeeded for
ImageView. We should also check with the content drawable of the
ImageView besides its foreground or background.

Bug: 62141891
Test: cts-tradefed run singleCommand cts --skip-device-info
--skip-preconditions --abi armeabi-v7a -m CtsViewTestCases -t
android.view.cts.View_DefaultFocusHighlightTest#testIsDefaultFocusHighlightNeeded

Change-Id: Iaf12a5863d7760d9361d0196a46de07a9ccda74e