Return texture frame when dropping frames in CameraCapturer.

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

Index: webrtc/api/android/java/src/org/webrtc/CameraCapturer.java
diff --git a/webrtc/api/android/java/src/org/webrtc/CameraCapturer.java b/webrtc/api/android/java/src/org/webrtc/CameraCapturer.java
index 2b0ffdcee798848d6d781cf2b9c9c6dc429ff940..6d4a1561c1cb70ece2b34f4f5e3f8e7a94b7a398 100644
--- a/webrtc/api/android/java/src/org/webrtc/CameraCapturer.java
+++ b/webrtc/api/android/java/src/org/webrtc/CameraCapturer.java
@@ -158,6 +158,7 @@ public abstract class CameraCapturer implements CameraVideoCapturer {
       synchronized (stateLock) {
         if (session != currentSession) {
           Logging.w(TAG, "onTextureFrameCaptured from another session.");
+          surfaceHelper.returnTextureFrame();
           return;
         }
         if (!firstFrameObserved) {