Add default dummy implementation of cricket::VideoRenderer::SetSize, to easy later removal.

talk/app/webrtc/videosource.cc

Index: talk/app/webrtc/videosource.cc
diff --git a/talk/app/webrtc/videosource.cc b/talk/app/webrtc/videosource.cc
index 5bd735af1c6f0bd97e97596bd477f0f01dbef08e..4b371e3ed58e771809905c4450b519e12b056d7f 100644
--- a/talk/app/webrtc/videosource.cc
+++ b/talk/app/webrtc/videosource.cc
@@ -304,8 +304,6 @@ class FrameInputWrapper : public cricket::VideoRenderer {
   virtual ~FrameInputWrapper() {}
 
   // VideoRenderer implementation.
-  bool SetSize(int width, int height, int reserved) override { return true; }
-
   bool RenderFrame(const cricket::VideoFrame* frame) override {
     if (!capturer_->IsRunning()) {
       return true;