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/ConnectionServiceAdapterServant.java

@@ -245,7 +245,8 @@ final class ConnectionServiceAdapterServant {
                 case MSG_ON_CONNECTION_EVENT: {
                     SomeArgs args = (SomeArgs) msg.obj;
                     try {
-                        mDelegate.onConnectionEvent((String) args.arg1, (String) args.arg2);
+                        mDelegate.onConnectionEvent((String) args.arg1, (String) args.arg2,
+                                (Bundle) args.arg3);
                     } finally {
                         args.recycle();
                     }
@@ -432,10 +433,11 @@ final class ConnectionServiceAdapterServant {
         }
 
         @Override
-        public final void onConnectionEvent(String connectionId, String event) {
+        public final void onConnectionEvent(String connectionId, String event, Bundle extras) {
             SomeArgs args = SomeArgs.obtain();
             args.arg1 = connectionId;
             args.arg2 = event;
+            args.arg3 = extras;
             mHandler.obtainMessage(MSG_ON_CONNECTION_EVENT, args).sendToTarget();
         }
     };