Send current bandwidth info event when buffering occurs

There is a dependent change in frameworks/av

Change-Id: Ic189654486936a501a1b45c5acb442753303d362
related-to-bug: 5883234

proprietary/wvm/include/WVMExtractorImpl.h

@@ -34,6 +34,7 @@ public:
 
     virtual sp<MetaData> getMetaData();
     virtual int64_t getCachedDurationUs(status_t *finalStatus);
+    virtual status_t getEstimatedBandwidthKbps(int32_t *kbps);
 
     virtual void setAdaptiveStreamingMode(bool adaptive);
     bool getAdaptiveStreamingMode() const;