Fix a reference leak when converting I420 VideoFrame to I420Frame.

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

Index: webrtc/sdk/android/api/org/webrtc/VideoRenderer.java
diff --git a/webrtc/sdk/android/api/org/webrtc/VideoRenderer.java b/webrtc/sdk/android/api/org/webrtc/VideoRenderer.java
index a118efe5feb4e0b7a4018ceb7f9807cd6cbebdd2..623f6b94cc7a4bfac1dc447d3dd2641ef1bb3584 100644
--- a/webrtc/sdk/android/api/org/webrtc/VideoRenderer.java
+++ b/webrtc/sdk/android/api/org/webrtc/VideoRenderer.java
@@ -104,6 +104,7 @@ public class VideoRenderer {
         this.yuvPlanes = null;
       } else {
         VideoFrame.I420Buffer i420Buffer = buffer.toI420();
+        buffer.release();
         this.yuvFrame = true;
         this.yuvStrides =
             new int[] {i420Buffer.getStrideY(), i420Buffer.getStrideU(), i420Buffer.getStrideV()};