Taskbar drag starts internal pre-drag before system drag

- TaskbarDragController now extends DragController.
- Currently there is no pre-drag condition, so we immediately get onDragStart(), which starts the system global drag (which cancels the original internal drag).
- Make the original view invisible during the drag and drop operation, across both internal and system drag events.
- No longer handle onDragEvent() in TaskbarView, as TaskbarDragController handles all of it now.

Test: Drag and drop from taskbar still works (bonus: starts from the correct registration point that you touched down on). Locally added a PreDragCondition and verified a seamless handoff to system drag and drop when the pre drag end condition was met.
Bug: 182981908
Change-Id: I6bf48141a5eedfc6db6f461258e880ef8146e733
diff --git a/src/com/android/launcher3/BubbleTextView.java b/src/com/android/launcher3/BubbleTextView.java
index 7866786..150db1e 100644
--- a/src/com/android/launcher3/BubbleTextView.java
+++ b/src/com/android/launcher3/BubbleTextView.java
@@ -413,7 +413,7 @@
         }
     }
 
-    void clearPressedBackground() {
+    public void clearPressedBackground() {
         setPressed(false);
         setStayPressed(false);
     }
@@ -859,8 +859,9 @@
         switch (display) {
             case DISPLAY_ALL_APPS:
                 return grid.allAppsIconSizePx;
-            case DISPLAY_WORKSPACE:
             case DISPLAY_FOLDER:
+                return grid.folderChildIconSizePx;
+            case DISPLAY_WORKSPACE:
             default:
                 return grid.iconSizePx;
         }
diff --git a/src/com/android/launcher3/dragndrop/DragController.java b/src/com/android/launcher3/dragndrop/DragController.java
index 5731db4..1e0edac 100644
--- a/src/com/android/launcher3/dragndrop/DragController.java
+++ b/src/com/android/launcher3/dragndrop/DragController.java
@@ -74,7 +74,7 @@
     /** Coordinate for last touch event **/
     protected final Point mLastTouch = new Point();
 
-    private final Point mTmpPoint = new Point();
+    protected final Point mTmpPoint = new Point();
 
     protected DropTarget.DragObject mDragObject;
 
@@ -317,7 +317,7 @@
         mDragObject.dragView.animateTo(mMotionDown.x, mMotionDown.y, onCompleteRunnable, duration);
     }
 
-    private void callOnDragEnd() {
+    protected void callOnDragEnd() {
         if (mIsInPreDrag && mOptions.preDragCondition != null) {
             mOptions.preDragCondition.onPreDragEnd(mDragObject, false /* dragStarted*/);
         }
@@ -343,7 +343,7 @@
     /**
      * Clamps the position to the drag layer bounds.
      */
-    private Point getClampedDragLayerPos(float x, float y) {
+    protected Point getClampedDragLayerPos(float x, float y) {
         mActivity.getDragLayer().getLocalVisibleRect(mRectTemp);
         mTmpPoint.x = (int) Math.max(mRectTemp.left, Math.min(x, mRectTemp.right - 1));
         mTmpPoint.y = (int) Math.max(mRectTemp.top, Math.min(y, mRectTemp.bottom - 1));
@@ -390,7 +390,7 @@
             return false;
         }
 
-        Point dragLayerPos = getClampedDragLayerPos(ev.getX(), ev.getY());
+        Point dragLayerPos = getClampedDragLayerPos(getX(ev), getY(ev));
         mLastTouch.set(dragLayerPos.x,  dragLayerPos.y);
         if (ev.getAction() == MotionEvent.ACTION_DOWN) {
             // Remember location of down touch
@@ -403,6 +403,14 @@
         return mDragDriver != null && mDragDriver.onInterceptTouchEvent(ev);
     }
 
+    protected float getX(MotionEvent ev) {
+        return ev.getX();
+    }
+
+    protected float getY(MotionEvent ev) {
+        return ev.getY();
+    }
+
     /**
      * Call this from a drag source view.
      */
diff --git a/src/com/android/launcher3/dragndrop/DragDriver.java b/src/com/android/launcher3/dragndrop/DragDriver.java
index d4ce308..72e47e5 100644
--- a/src/com/android/launcher3/dragndrop/DragDriver.java
+++ b/src/com/android/launcher3/dragndrop/DragDriver.java
@@ -165,8 +165,11 @@
      * Class for driving an internal (i.e. not using framework) drag/drop operation.
      */
     static class InternalDragDriver extends DragDriver {
+        private final DragController mDragController;
+
         InternalDragDriver(DragController dragController, Consumer<MotionEvent> sec) {
             super(dragController, sec);
+            mDragController = dragController;
         }
 
         @Override
@@ -176,11 +179,14 @@
 
             switch (action) {
                 case MotionEvent.ACTION_MOVE:
-                    mEventListener.onDriverDragMove(ev.getX(), ev.getY());
+                    mEventListener.onDriverDragMove(mDragController.getX(ev),
+                            mDragController.getY(ev));
                     break;
                 case MotionEvent.ACTION_UP:
-                    mEventListener.onDriverDragMove(ev.getX(), ev.getY());
-                    mEventListener.onDriverDragEnd(ev.getX(), ev.getY());
+                    mEventListener.onDriverDragMove(mDragController.getX(ev),
+                            mDragController.getY(ev));
+                    mEventListener.onDriverDragEnd(mDragController.getX(ev),
+                            mDragController.getY(ev));
                     break;
                 case MotionEvent.ACTION_CANCEL:
                     mEventListener.onDriverDragCancel();
@@ -197,7 +203,8 @@
 
             switch (action) {
                 case MotionEvent.ACTION_UP:
-                    mEventListener.onDriverDragEnd(ev.getX(), ev.getY());
+                    mEventListener.onDriverDragEnd(mDragController.getX(ev),
+                            mDragController.getY(ev));
                     break;
                 case MotionEvent.ACTION_CANCEL:
                     mEventListener.onDriverDragCancel();