This is an initial cleanup step, aiming to delete the
webrtc::VideoRenderer class, replacing it by rtc::VideoSinkInterface.

The next step is to convert all places where a renderer is attached to
rtc::VideoSourceInterface, and at that point, the
SmoothsRenderedFrames method can be replaced by a flag
rtc::VideoSinkWants::smoothed_frames.

Delete unused method IsTextureSupported.
Delete unused time argument to RenderFrame.
Let webrtc::VideoRenderer inherit rtc::VideoSinkInterface. Rename RenderFrame --> OnFrame.

TBR=kjellander@webrtc.org
BUG=webrtc:5426

Review URL: https://codereview.webrtc.org/1814763002

Cr-Commit-Position: refs/heads/master@{#12070}
diff --git a/webrtc/test/linux/glx_renderer.h b/webrtc/test/linux/glx_renderer.h
index c117281..4a758db 100644
--- a/webrtc/test/linux/glx_renderer.h
+++ b/webrtc/test/linux/glx_renderer.h
@@ -26,8 +26,7 @@
                              size_t height);
   virtual ~GlxRenderer();
 
-  void RenderFrame(const webrtc::VideoFrame& frame, int delta) override;
-  bool IsTextureSupported() const override { return false; }
+  void OnFrame(const webrtc::VideoFrame& frame) override;
 
  private:
   GlxRenderer(size_t width, size_t height);