Merge "Do not calculate drag area with no valid display context." into main

    @Override

    @NonNull

    Rect calculateValidDragArea() {

        final Context displayContext = mDisplayController.getDisplayContext(mTaskInfo.displayId);

        if (displayContext == null) return new Rect();

        final int leftButtonsWidth = loadDimensionPixelSize(mContext.getResources(),

                R.dimen.caption_left_buttons_width);

        // On a smaller screen, don't require as much empty space on screen, as offscreen

        // drags will be restricted too much.

        final int requiredEmptySpaceId = mDisplayController.getDisplayContext(mTaskInfo.displayId)

        final int requiredEmptySpaceId = displayContext

                .getResources().getConfiguration().smallestScreenWidthDp >= 600

                ? R.dimen.freeform_required_visible_empty_space_in_header :

                R.dimen.small_screen_required_visible_empty_space_in_header;