Finalize MEP functionality.

1) Finish plumbing of PULLING_CALL state.
2) Add new disconnect cause used when maximum number of calls across
all devices has been reached.
3) Add PII mask for toString of ImsExternalCallState.

Bug: 29522023
Change-Id: I78a0a9f3c3d846cfc58a1c5bcc6f105027602cbc

telecomm/java/android/telecom/ConnectionServiceAdapter.java

@@ -142,6 +142,21 @@ final class ConnectionServiceAdapter implements DeathRecipient {
         }
     }
 
+    /**
+     * Sets a call's state to pulling (e.g. a call with {@link Connection#PROPERTY_IS_EXTERNAL_CALL}
+     * is being pulled to the local device.
+     *
+     * @param callId The unique ID of the call whose state is changing to dialing.
+     */
+    void setPulling(String callId) {
+        for (IConnectionServiceAdapter adapter : mAdapters) {
+            try {
+                adapter.setPulling(callId);
+            } catch (RemoteException e) {
+            }
+        }
+    }
+
     /**
      * Sets a call's state to disconnected.
      *