Fix NPE crash when mPhone is null

Bug:17609710
Change-Id: Idb99feb6f15fd29809adde51cda1eb0d44e20101
diff --git a/telecomm/java/android/telecom/InCallService.java b/telecomm/java/android/telecom/InCallService.java
index fa12756..11da0f2 100644
--- a/telecomm/java/android/telecom/InCallService.java
+++ b/telecomm/java/android/telecom/InCallService.java
@@ -59,6 +59,10 @@
     private final Handler mHandler = new Handler(Looper.getMainLooper()) {
         @Override
         public void handleMessage(Message msg) {
+            if (mPhone == null && msg.what != MSG_SET_IN_CALL_ADAPTER) {
+                return;
+            }
+
             switch (msg.what) {
                 case MSG_SET_IN_CALL_ADAPTER:
                     mPhone = new Phone(new InCallAdapter((IInCallAdapter) msg.obj));