Rename EncodedImage::_buffer --> buffer_, and make private

Bug: webrtc:9378
Change-Id: I0a0636077b270a7c73bafafb958132fa648aca70
Reviewed-on: https://webrtc-review.googlesource.com/c/117722
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26294}
diff --git a/modules/video_coding/frame_object.cc b/modules/video_coding/frame_object.cc
index 6fcb573..4f5f9d4 100644
--- a/modules/video_coding/frame_object.cc
+++ b/modules/video_coding/frame_object.cc
@@ -55,7 +55,7 @@
   SetPlayoutDelay(first_packet->video_header.playout_delay);
 
   AllocateBitstreamBuffer(frame_size);
-  bool bitstream_copied = packet_buffer_->GetBitstream(*this, _buffer);
+  bool bitstream_copied = packet_buffer_->GetBitstream(*this, data());
   RTC_DCHECK(bitstream_copied);
   _encodedWidth = first_packet->width;
   _encodedHeight = first_packet->height;
@@ -179,7 +179,7 @@
                                       ? EncodedImage::kBufferPaddingBytesH264
                                       : 0);
   if (capacity() < new_size) {
-    delete[] _buffer;
+    delete[] data();
     set_buffer(new uint8_t[new_size], new_size);
   }