Java VideoRenderer.Callbacks: Make renderFrame() interface asynchronous

talk/app/webrtc/java/android/org/webrtc/VideoCapturerAndroid.java

Index: talk/app/webrtc/java/android/org/webrtc/VideoCapturerAndroid.java
diff --git a/talk/app/webrtc/java/android/org/webrtc/VideoCapturerAndroid.java b/talk/app/webrtc/java/android/org/webrtc/VideoCapturerAndroid.java
index 00034fc1433cbb5324555ca53da41435dea486e6..d4251f6021a6829f54daa51f7144a2bb15dd2cbe 100644
--- a/talk/app/webrtc/java/android/org/webrtc/VideoCapturerAndroid.java
+++ b/talk/app/webrtc/java/android/org/webrtc/VideoCapturerAndroid.java
@@ -223,6 +223,12 @@ public class VideoCapturerAndroid extends VideoCapturer implements PreviewCallba
     return CameraEnumerationAndroid.supportedFormats.get(id);
   }
 
+  // Return a list of timestamps for the frames that have been sent out, but not returned yet.
+  // Useful for logging and testing.
+  public String pendingFramesTimeStamps() {
+    return videoBuffers.pendingFramesTimeStamps();
+  }
+
   private VideoCapturerAndroid() {
     Log.d(TAG, "VideoCapturerAndroid");
   }