wip 3029324: Implement new drag feedback

- Show page borders when dragging
- Enlarge scroll region (landscape only)
- When inside scroll region, show green border on adjacent page

src/com/android/launcher2/DragController.java

@@ -56,8 +56,8 @@ public class DragController {
     private static final int SCROLL_OUTSIDE_ZONE = 0;
     private static final int SCROLL_WAITING_IN_ZONE = 1;
 
-    private static final int SCROLL_LEFT = 0;
-    private static final int SCROLL_RIGHT = 1;
+    static final int SCROLL_LEFT = 0;
+    static final int SCROLL_RIGHT = 1;
 
     private Context mContext;
     private Handler mHandler;
@@ -156,6 +156,10 @@ public class DragController {
         mScrollZone = context.getResources().getDimensionPixelSize(R.dimen.scroll_zone);
     }
 
+    public boolean dragging() {
+        return mDragging;
+    }
+
     /**
      * Starts a drag.
      *
@@ -487,18 +491,21 @@ public class DragController {
                 mScrollState = SCROLL_WAITING_IN_ZONE;
                 mScrollRunnable.setDirection(SCROLL_LEFT);
                 mHandler.postDelayed(mScrollRunnable, SCROLL_DELAY);
+                mDragScroller.onEnterScrollArea(SCROLL_LEFT);
             }
         } else if (!inDeleteRegion && x > mScrollView.getWidth() - mScrollZone) {
             if (mScrollState == SCROLL_OUTSIDE_ZONE) {
                 mScrollState = SCROLL_WAITING_IN_ZONE;
                 mScrollRunnable.setDirection(SCROLL_RIGHT);
                 mHandler.postDelayed(mScrollRunnable, SCROLL_DELAY);
+                mDragScroller.onEnterScrollArea(SCROLL_RIGHT);
             }
         } else {
             if (mScrollState == SCROLL_WAITING_IN_ZONE) {
                 mScrollState = SCROLL_OUTSIDE_ZONE;
                 mScrollRunnable.setDirection(SCROLL_RIGHT);
                 mHandler.removeCallbacks(mScrollRunnable);
+                mDragScroller.onExitScrollArea();
             }
         }
     }