Fixing widget sheet not scrolled using external mouse

> Fixing crash when some properties are not initialized if draw is not called
> Adding robolectic support for UI testing
> Adding robo tests to verify workspace, all-apps, widgets and folder scrolling

Bug: 147312357
Change-Id: Id7756e07f06396359e441cdff2e4f992bdcb97bb

src/com/android/launcher3/allapps/AllAppsPagedView.java

@@ -83,7 +83,7 @@ public class AllAppsPagedView extends PagedView<PersonalWorkSlidingTabStrip> {
     }
 
     @Override
-    protected boolean isVerticalScrollable() {
-        return false;
+    protected boolean canScroll(float absVScroll, float absHScroll) {
+        return (absHScroll > absVScroll) && super.canScroll(absVScroll, absHScroll);
     }
 }