Implement PSTN call services

Change-Id: I6239f0d9c68a3c08b63553b3fca266631211c759
diff --git a/src/com/android/phone/PhoneUtils.java b/src/com/android/phone/PhoneUtils.java
index 69a7995..4ceefe1 100644
--- a/src/com/android/phone/PhoneUtils.java
+++ b/src/com/android/phone/PhoneUtils.java
@@ -2627,7 +2627,7 @@
     /**
      * @return true if this device supports voice calls using the built-in SIP stack.
      */
-    static boolean isVoipSupported() {
+    public static boolean isVoipSupported() {
         return sVoipSupported;
     }