IMS: Set phone account in IMS Conference object.

Get phone account from conference host connection and set
it to ImsConference while constructing.

Bug: 18690773
Change-Id: I1f66927a9b7905e005196365f3b318ef5b49dd3e
diff --git a/src/com/android/services/telephony/ImsConference.java b/src/com/android/services/telephony/ImsConference.java
index 528b65d..5a15a47 100644
--- a/src/com/android/services/telephony/ImsConference.java
+++ b/src/com/android/services/telephony/ImsConference.java
@@ -179,6 +179,13 @@
         super(null);
         mTelephonyConnectionService = telephonyConnectionService;
         setConferenceHost(conferenceHost);
+        if (conferenceHost != null && conferenceHost.getCall() != null
+                && conferenceHost.getCall().getPhone() != null) {
+            mPhoneAccount = PhoneUtils.makePstnPhoneAccountHandle(
+                    conferenceHost.getCall().getPhone());
+            Log.v(this, "set phacc to " + mPhoneAccount);
+        }
+
         setConnectionCapabilities(
                 Connection.CAPABILITY_SUPPORT_HOLD |
                 Connection.CAPABILITY_HOLD |