Add API support for multi-endpoint.

This CL includes changes required to support multi-endpoint (see the
design doc linked off the bug).

Main changes include:
- support for indicating if a call/connection is "external" to the device.
- support for indicating if an external call can be pulled from the
remote device to the local device.
- API used to initiate a pull of a call external to the current device to
the current device.
- Made the "connection event" API public (was previously @hide); this will
be used to support passing some error events involving pulling calls to
the incall ui.
- Added new InCallService metadata which will be used to determine if an
InCallService wants to be informed of external calls.
- New disconnect causes which will be used to expose the fact that a
multi-endpoint call was answered elsewhere and that a call ended because
it was pulled to another device.
- New call log call types to indicate if calls were answered elsewhere
or pulled to another device.

Bug: 27458894
Change-Id: I423f64ff965b5e50194635a51868c327782db2a1

telecomm/java/android/telecom/Phone.java

@@ -17,6 +17,7 @@
 package android.telecom;
 
 import android.annotation.SystemApi;
+import android.os.Bundle;
 import android.util.ArrayMap;
 
 import java.util.Collections;
@@ -190,6 +191,13 @@ public final class Phone {
         fireSilenceRinger();
     }
 
+    final void internalOnConnectionEvent(String telecomId, String event, Bundle extras) {
+        Call call = mCallByTelecomCallId.get(telecomId);
+        if (call != null) {
+            call.internalOnConnectionEvent(event, extras);
+        }
+    }
+
     /**
      * Called to destroy the phone and cleanup any lingering calls.
      */