Revert of Add content type information to encoded images and corresponding rtp extension header

webrtc/modules/video_coding/encoded_frame.h

Index: webrtc/modules/video_coding/encoded_frame.h
diff --git a/webrtc/modules/video_coding/encoded_frame.h b/webrtc/modules/video_coding/encoded_frame.h
index 96f9d00d06e77780e9e6b5ac7b9f3125d63396f1..840cd2056d594562799957559948f461e24b56a7 100644
--- a/webrtc/modules/video_coding/encoded_frame.h
+++ b/webrtc/modules/video_coding/encoded_frame.h
@@ -77,12 +77,8 @@
   */
   VideoRotation rotation() const { return rotation_; }
   /**
-   *  Get video content type
-   */
-  VideoContentType contentType() const { return content_type_; }
-  /**
-   *   True if this frame is complete, false otherwise
-   */
+  *   True if this frame is complete, false otherwise
+  */
   bool Complete() const { return _completeFrame; }
   /**
   *   True if there's a frame missing before this frame