In screenshare mode, suppress VP8 bitrate overshoot and increase quality

webrtc/modules/video_coding/main/source/generic_encoder.h

Index: webrtc/modules/video_coding/main/source/generic_encoder.h
diff --git a/webrtc/modules/video_coding/main/source/generic_encoder.h b/webrtc/modules/video_coding/main/source/generic_encoder.h
index a72277214e046bdf66cd65e0cc354ab08c06d12c..2f6f283c498ee2335630933c884705348b655bc6 100644
--- a/webrtc/modules/video_coding/main/source/generic_encoder.h
+++ b/webrtc/modules/video_coding/main/source/generic_encoder.h
@@ -55,6 +55,7 @@ public:
     void SetInternalSource(bool internalSource) { _internalSource = internalSource; };
 
     void SetRotation(VideoRotation rotation) { _rotation = rotation; }
+    bool GetAndResetFrameProduced();
 
 private:
     VCMPacketizationCallback* _sendCallback;
@@ -65,6 +66,8 @@ private:
 
     EncodedImageCallback* post_encode_callback_;
 
+    bool frame_produced_;
+
 #ifdef DEBUG_ENCODER_BIT_STREAM
     FILE* _bitStreamAfterEncoder;
 #endif
@@ -149,6 +152,7 @@ private:
     const bool internal_source_;
     mutable rtc::CriticalSection rates_lock_;
     VideoRotation rotation_;
+    bool is_screenshare_;
 }; // end of VCMGenericEncoder class
 
 }  // namespace webrtc