Enable Continual gathering in apprtcdemo.
This will help test or debug the continual gathering policy.

BUG=

Review URL: https://codereview.webrtc.org/1812593002

Cr-Commit-Position: refs/heads/master@{#12038}
diff --git a/webrtc/examples/androidapp/src/org/appspot/apprtc/PeerConnectionClient.java b/webrtc/examples/androidapp/src/org/appspot/apprtc/PeerConnectionClient.java
index ecd0da4..1ce7770 100644
--- a/webrtc/examples/androidapp/src/org/appspot/apprtc/PeerConnectionClient.java
+++ b/webrtc/examples/androidapp/src/org/appspot/apprtc/PeerConnectionClient.java
@@ -459,6 +459,7 @@
     rtcConfig.tcpCandidatePolicy = PeerConnection.TcpCandidatePolicy.DISABLED;
     rtcConfig.bundlePolicy = PeerConnection.BundlePolicy.MAXBUNDLE;
     rtcConfig.rtcpMuxPolicy = PeerConnection.RtcpMuxPolicy.REQUIRE;
+    rtcConfig.continualGatheringPolicy = PeerConnection.ContinualGatheringPolicy.GATHER_CONTINUALLY;
     // Use ECDSA encryption.
     rtcConfig.keyType = PeerConnection.KeyType.ECDSA;