Fix/suppress all javac warnings.

This is done in preparation to make all javac warnings into errors for
WebRTC targets.

Bug: webrtc:6597
Change-Id: I402043157bd75943adf0de52111e5a1bb179c6d1
Reviewed-on: https://webrtc-review.googlesource.com/15104
Commit-Queue: Sami Kalliomäki <sakal@webrtc.org>
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20450}

sdk/android/api/org/webrtc/VideoFileRenderer.java

@@ -84,6 +84,9 @@ public class VideoFileRenderer implements VideoRenderer.Callbacks {
     });
   }
 
+  // TODO(sakal): yuvConverter.convert is deprecated. This will be removed once this file is updated
+  // to implement VideoSink instead of VideoRenderer.Callbacks.
+  @SuppressWarnings("deprecation")
   private void renderFrameOnRenderThread(VideoRenderer.I420Frame frame) {
     final float frameAspectRatio = (float) frame.rotatedWidth() / (float) frame.rotatedHeight();