Add Launcher.onDragStarted

Change-Id: Iac59685211905580460d0a0a16d9c7f00c61fac9
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index f1ce235..c18574a 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -2596,6 +2596,8 @@
         }
     }
 
+    public void onDragStarted(View view) {}
+
     /**
      * Called when the user stops interacting with the launcher.
      * This implies that the user is now on the homescreen and is not doing housekeeping.