Update from https://crrev.com/316786

net/quic/quic_data_writer.h

Index: net/quic/quic_data_writer.h
diff --git a/net/quic/quic_data_writer.h b/net/quic/quic_data_writer.h
index 8204c3af2c24bf4ed0c4fe40b3eac07e15f65b2f..4b5958efe57d18dd03d4053b361d2fade2602a5d 100644
--- a/net/quic/quic_data_writer.h
+++ b/net/quic/quic_data_writer.h
@@ -20,20 +20,20 @@ namespace net {
 // This class provides facilities for packing QUIC data.
 //
 // The QuicDataWriter supports appending primitive values (int, string, etc)
-// to a frame instance.  The QuicDataWriter grows its internal memory buffer
-// dynamically to hold the sequence of primitive values.   The internal memory
-// buffer is exposed as the "data" of the QuicDataWriter.
+// to a frame instance.  The internal memory buffer is exposed as the "data"
+// of the QuicDataWriter.
 class NET_EXPORT_PRIVATE QuicDataWriter {
  public:
-  explicit QuicDataWriter(size_t length);
+  // Creates a QuicDataWriter where |buffer| is not owned.
+  QuicDataWriter(size_t size, char* buffer);
 
   ~QuicDataWriter();
 
   // Returns the size of the QuicDataWriter's data.
   size_t length() const { return length_; }
 
-  // Takes the buffer from the QuicDataWriter.
-  char* take();
+  // Retrieves the buffer from the QuicDataWriter without changing ownership.
+  char* data();
 
   // Methods for adding to the payload.  These values are appended to the end
   // of the QuicDataWriter payload. Note - binary integers are written in