Refactor / Cleanup / Simplify a bunch of dnd related rendering / animation

Addresses:
=> Fix folder icon drop location mapping (was very far off)
=> Fix BubbleTextView drop animation shifted by a few pixels
=> Get rid multiple unnecessary calls to setDragMode(none), was breaking
   some of the reorder flow; still some issues to address here.
=> Fix folder icon parallax (didn't work when the folder had a dot)

Test: manual

Change-Id: I5959cf341996f75d30212353ec096ed25bf40ea5
diff --git a/src/com/android/launcher3/DropTarget.java b/src/com/android/launcher3/DropTarget.java
index a32fd12..43ec5a6 100644
--- a/src/com/android/launcher3/DropTarget.java
+++ b/src/com/android/launcher3/DropTarget.java
@@ -23,6 +23,7 @@
 import com.android.launcher3.config.FeatureFlags;
 import com.android.launcher3.dragndrop.DragOptions;
 import com.android.launcher3.dragndrop.DragView;
+import com.android.launcher3.dragndrop.DraggableView;
 import com.android.launcher3.folder.FolderNameProvider;
 
 /**
@@ -72,6 +73,10 @@
 
         public FolderNameProvider folderNameProvider;
 
+        /** The source view (ie. icon, widget etc.) that is being dragged and which the
+         * DragView represents. May be an actual View class or a virtual stand-in */
+        public DraggableView originalView = null;
+
         public DragObject(Context context) {
             if (FeatureFlags.FOLDER_NAME_SUGGEST.get()) {
                 folderNameProvider = FolderNameProvider.newInstance(context);