Make PacketReader/PacketWriter interfaces async-only.

blimp/net/packet_writer.h

Index: blimp/net/packet_writer.h
diff --git a/blimp/net/packet_writer.h b/blimp/net/packet_writer.h
index 1ac2126bd1e4f298e7e4cb17201199e076760657..a1402ae3d157688e5672c34bda9b462407b28195 100644
--- a/blimp/net/packet_writer.h
+++ b/blimp/net/packet_writer.h
@@ -21,13 +21,10 @@ class BLIMP_NET_EXPORT PacketWriter {
  public:
   virtual ~PacketWriter() {}
 
-  // Writes a packet of at least one byte in size to a connection.
-  //
-  // Returns net::OK or an error code if the operation executed successfully.
-  // Returns ERR_IO_PENDING if the operation will be executed asynchronously.
-  //     |cb| is later invoked with net::OK or an error code.
-  virtual int WritePacket(scoped_refptr<net::DrainableIOBuffer> data,
-                          const net::CompletionCallback& callback) = 0;
+  // Invokes |cb| with net::OK if the write operation executed successfully.
+  // All other values indicate errors.

[Wez, 2015/11/20 23:42:13]

nit: "indicate errors" is vague; be explicit as to whether they are recoverable
or not?

Do we want to reserve ERR_IO_PENDING or something to mean "couldn't buffer this
right now, wait til an earlier operation completes"?

[Kevin M, 2015/11/24 21:34:36]

I'm not sure if we want that convention? That seems like it would be useful in
the case where there would be multiple data producers feeding into the same
writer. In our case, it's just the buffer that's pushing data into the writer.

+  virtual void WritePacket(scoped_refptr<net::DrainableIOBuffer> data,
+                           const net::CompletionCallback& callback) = 0;
 };
 
 }  // namespace blimp