Delete VCMEncodedFrame methods Buffer and MutableBuffer

Replaced by inherited method EncodedImage::data().

Bug: webrtc:9378
Change-Id: I4ec75148f578c72ffb407f9cbf6b4232cc9cfcf6
Reviewed-on: https://webrtc-review.googlesource.com/c/116962
Reviewed-by: Erik Språng <sprang@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26212}
diff --git a/modules/video_coding/encoded_frame.h b/modules/video_coding/encoded_frame.h
index 978ee5c..2cdcff9 100644
--- a/modules/video_coding/encoded_frame.h
+++ b/modules/video_coding/encoded_frame.h
@@ -56,17 +56,8 @@
   const webrtc::EncodedImage& EncodedImage() const {
     return static_cast<const webrtc::EncodedImage&>(*this);
   }
-  /**
-   *   Get pointer to frame buffer
-   */
-  const uint8_t* Buffer() const { return _buffer; }
-  /**
-   *   Get pointer to frame buffer that can be mutated.
-   */
-  uint8_t* MutableBuffer() { return _buffer; }
-  /**
-   *   Frame RTP timestamp (90kHz)
-   */
+
+  using EncodedImage::data;
   using EncodedImage::set_size;
   using EncodedImage::SetSpatialIndex;
   using EncodedImage::SetTimestamp;