Moving drag-drop related code into a separate package.

This is per an earlier CR comment "we should probably move all this code to its own package (launcher3.dragndrop) in a separate cl".

I'm not moving DragSource because it's referred from gsa code.

Bug: 22609426
Change-Id: Ia7204dab99c0c395c66b77143a2d60411153f5f3
diff --git a/src/com/android/launcher3/PagedView.java b/src/com/android/launcher3/PagedView.java
index 3702cda..28e3367 100644
--- a/src/com/android/launcher3/PagedView.java
+++ b/src/com/android/launcher3/PagedView.java
@@ -63,7 +63,7 @@
     // the min drag distance for a fling to register, to prevent random page shifts
     private static final int MIN_LENGTH_FOR_FLING = 25;
 
-    protected static final int PAGE_SNAP_ANIMATION_DURATION = 750;
+    public static final int PAGE_SNAP_ANIMATION_DURATION = 750;
     protected static final int SLOW_PAGE_SNAP_ANIMATION_DURATION = 950;
 
     private static final float RETURN_TO_ORIGINAL_PAGE_THRESHOLD = 0.33f;
@@ -381,7 +381,7 @@
     /**
      * Returns the index of page to be shown immediately afterwards.
      */
-    int getNextPage() {
+    public int getNextPage() {
         return (mNextPage != INVALID_PAGE) ? mNextPage : mCurrentPage;
     }