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

src/com/android/launcher3/widget/NavigableAppWidgetHostView.java

@@ -24,12 +24,15 @@ import android.view.View;
 import android.view.ViewDebug;
 import android.view.ViewGroup;
 
+import com.android.launcher3.dragndrop.DraggableView;
+
 import java.util.ArrayList;
 
 /**
  * Extension of AppWidgetHostView with support for controlled keyboard navigation.
  */
-public abstract class NavigableAppWidgetHostView extends AppWidgetHostView {
+public abstract class NavigableAppWidgetHostView extends AppWidgetHostView
+        implements DraggableView {
 
     @ViewDebug.ExportedProperty(category = "launcher")
     private boolean mChildrenFocused;
@@ -133,4 +136,14 @@ public abstract class NavigableAppWidgetHostView extends AppWidgetHostView {
         // The host view's background changes when selected, to indicate the focus is inside.
         setSelected(childIsFocused);
     }
+
+    @Override
+    public int getViewType() {
+        return DRAGGABLE_WIDGET;
+    }
+
+    @Override
+    public void getVisualDragBounds(Rect bounds) {
+        bounds.set(0, 0 , getMeasuredWidth(), getMeasuredHeight());
+    }
 }