Merge "Clean up IllegalStateException for page pairing" into sc-v2-dev

            if (isTwoPanelEnabled() && !(mDragSourceInternal.getParent() instanceof Hotseat)) {

                int pagePairScreenId = getScreenPair(dragObject.dragInfo.screenId);

                CellLayout pagePair = mWorkspaceScreens.get(pagePairScreenId);

                if (pagePair == null) {

                    // TODO: after http://b/198820019 is fixed, remove this

                    throw new IllegalStateException("Page pair is null, "

                            + "dragScreenId: " + dragObject.dragInfo.screenId

                            + ", pagePairScreenId: " + pagePairScreenId

                            + ", mScreenOrder: " + mScreenOrder.toConcatString()

                    );

                }

                dragSourceChildCount += pagePair.getShortcutsAndWidgets().getChildCount();

            }