Initial commit of taskbar stashing

- Added StashedHandleViewController to provide properties such as ViewOutlineProvider to animate the handle that's shown in place of taskbar while it's stashed
- Added TaskbarStashController to coordinate the stashed state, including orchestrating the animation across taskbar controllers
- Added TaskbarStashInput consumer to detect long press in the nav region when taskbar is stashed

Behavior:
- Long pressing taskbar background animates to the stashed state by morphing the TaskbarView into the stashed handle view and offsetting the background offscreen
- We persist the stashed state across app launches and reboot; to unstash, long press the stashed handle
- We also visually unstash when going back home

Test: long press tasbkar background when in an app to stash it, long press the resulting stashed handle to unstash; while stashed, swipe up to home to also unstash until launching another app
Bug: 189503603
Change-Id: I698eff785388dff1ef717c76879719d6af236c2d

quickstep/src/com/android/launcher3/taskbar/TaskbarView.java

@@ -94,8 +94,10 @@ public class TaskbarView extends FrameLayout implements FolderIcon.FolderIconPar
 
     protected void init(TaskbarViewController.TaskbarViewCallbacks callbacks) {
         mControllerCallbacks = callbacks;
-        mIconClickListener = mControllerCallbacks.getOnClickListener();
-        mIconLongClickListener = mControllerCallbacks.getOnLongClickListener();
+        mIconClickListener = mControllerCallbacks.getIconOnClickListener();
+        mIconLongClickListener = mControllerCallbacks.getIconOnLongClickListener();
+
+        setOnLongClickListener(mControllerCallbacks.getBackgroundOnLongClickListener());
     }
 
     private void removeAndRecycle(View view) {
@@ -235,6 +237,10 @@ public class TaskbarView extends FrameLayout implements FolderIcon.FolderIconPar
         return isShown() && mIconLayoutBounds.contains(xInOurCoordinates, yInOurCoorindates);
     }
 
+    public Rect getIconLayoutBounds() {
+        return mIconLayoutBounds;
+    }
+
     // FolderIconParent implemented methods.
 
     @Override