Removed SSRC knowledge from ViEEncoder.

webrtc/modules/video_coding/include/video_coding.h

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 238 matching lines @@
   //                     < 0,    on error.
   virtual int32_t AddVideoFrame(
       const VideoFrame& videoFrame,
       const VideoContentMetrics* contentMetrics = NULL,
       const CodecSpecificInfo* codecSpecificInfo = NULL) = 0;
 
   // Next frame encoded should be an intra frame (keyframe).
   //
   // Return value      : VCM_OK, on success.
   //                     < 0,    on error.
-  virtual int32_t IntraFrameRequest(int stream_index) = 0;
+  virtual int32_t IntraFrameRequest(size_t stream_index) = 0;
 
   // Frame Dropper enable. Can be used to disable the frame dropping when the
   // encoder
   // over-uses its bit rate. This API is designed to be used when the encoded
   // frames
   // are supposed to be stored to an AVI file, or when the I420 codec is used
   // and the
   // target bit rate shouldn't affect the frame rate.
   //
   // Input:
@@ skipping 244 matching lines @@
 
   virtual void RegisterPostEncodeImageCallback(
       EncodedImageCallback* post_encode_callback) = 0;
   // Releases pending decode calls, permitting faster thread shutdown.
   virtual void TriggerDecoderShutdown() = 0;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_VIDEO_CODING_INCLUDE_VIDEO_CODING_H_