Add TODO comments on deprecated VideoFrame methods.

webrtc/media/base/videoframe.h

Index: webrtc/media/base/videoframe.h
diff --git a/webrtc/media/base/videoframe.h b/webrtc/media/base/videoframe.h
index 4015f906f93c4ee0894d7a7167f4d62bf1b7b7bb..1f282c5f290fba9576cd2207c0c0d30af088caa3 100644
--- a/webrtc/media/base/videoframe.h
+++ b/webrtc/media/base/videoframe.h
@@ -19,6 +19,10 @@
 namespace cricket {
 
 // Represents a YUV420 (a.k.a. I420) video frame.
+
+// TODO(nisse): This class duplicates webrtc::VideoFrame. There's
+// ongoing work to merge the classes. See
+// https://bugs.chromium.org/p/webrtc/issues/detail?id=5682.
 class VideoFrame {
  public:
   VideoFrame() {}
@@ -54,22 +58,40 @@ class VideoFrame {
   // Make a shallow copy of the frame. The frame buffer itself is not copied.
   // Both the current and new VideoFrame will share a single reference-counted
   // frame buffer.
+
+  // TODO(nisse): Deprecated, to be deleted in the cricket::VideoFrame and
+  // webrtc::VideoFrame merge. To make a copy, use the cricket::WebRtcVideoFrame
+  // constructor passing video_frame_buffer(), rotation() and timestamp_us() as
+  // arguments.
   virtual VideoFrame *Copy() const = 0;
 
   // Return a copy of frame which has its pending rotation applied. The
   // ownership of the returned frame is held by this frame.
+
+  // TODO(nisse): Deprecated. Should be moved or deleted in the
+  // cricket::VideoFrame and webrtc::VideoFrame merge, possibly with a helper
+  // method on VideoFrameBuffer.
   virtual const VideoFrame* GetCopyWithRotationApplied() const = 0;
 
   // Converts the I420 data to RGB of a certain type such as ARGB and ABGR.
   // Returns the frame's actual size, regardless of whether it was written or
   // not (like snprintf). Parameters size and stride_rgb are in units of bytes.
   // If there is insufficient space, nothing is written.
+
+  // TODO(nisse): Deprecated. Should be moved or deleted in the
+  // cricket::VideoFrame and webrtc::VideoFrame merge. Use
+  // libyuv::ConvertFromI420 directly instead.
   virtual size_t ConvertToRgbBuffer(uint32_t to_fourcc,
                                     uint8_t* buffer,
                                     size_t size,
                                     int stride_rgb) const;
 
-  // Tests if sample is valid.  Returns true if valid.
+  // Tests if sample is valid. Returns true if valid.
+
+  // TODO(nisse): Deprecated. Should be deleted in the cricket::VideoFrame and
+  // webrtc::VideoFrame merge. Validation of sample_size possibly moved to
+  // libyuv::ConvertToI420. As an initial step, demote this method to protected
+  // status. Used only by WebRtcVideoFrame::Reset.
   static bool Validate(uint32_t fourcc,
                        int w,
                        int h,