Stubs for video and connection handoff

This CL adds two sets of APIs:
  - video handoff: switch the given call to video
  - connection handoff: switch the given call between wifi and cell

For now these APIs are just stubs to be implemented later.

Change-Id: Ie5894cb786482935095b1f44a49609eb69226f44
diff --git a/src/com/android/phone/CallCommandService.java b/src/com/android/phone/CallCommandService.java
index 5238911..175a0ed 100644
--- a/src/com/android/phone/CallCommandService.java
+++ b/src/com/android/phone/CallCommandService.java
@@ -268,4 +268,13 @@
         }
     }
 
+    @Override
+    public void videoHandoff(int callId) {
+        // TODO(sail): Implement this.
+    }
+
+    @Override
+    public void connectionHandoff(int callId) {
+        // TODO(sail): Implement this.
+    }
 }