Add onCameraDisconnected camera event.

webrtc/api/android/java/src/org/webrtc/Camera2Session.java

Index: webrtc/api/android/java/src/org/webrtc/Camera2Session.java
diff --git a/webrtc/api/android/java/src/org/webrtc/Camera2Session.java b/webrtc/api/android/java/src/org/webrtc/Camera2Session.java
index 6ff73c5aedb18d47d1241d8a60a875356260ec5f..ad4ffd69b11a29a6b03b97cfb730eacd70b7a33c 100644
--- a/webrtc/api/android/java/src/org/webrtc/Camera2Session.java
+++ b/webrtc/api/android/java/src/org/webrtc/Camera2Session.java
@@ -98,7 +98,14 @@ public class Camera2Session implements CameraSession {
     @Override
     public void onDisconnected(CameraDevice camera) {
       checkIsOnCameraThread();
-      reportError("Camera disconnected.");
+      final boolean startFailure = (captureSession == null);
+      state = SessionState.STOPPED;
+      stopInternal();
+      if (startFailure) {
+        callback.onFailure("Camera disconnected / evicted.");
+      } else {
+        events.onCameraDisconnected(Camera2Session.this);
+      }
     }
 
     @Override