Decouple Blimp transport output from BlimpConnections using MessagePort.

blimp/net/blimp_transport.h

Index: blimp/net/blimp_transport.h
diff --git a/blimp/net/blimp_transport.h b/blimp/net/blimp_transport.h
index e74bb164b9c745fe49ee94f6e61220099eb24e85..07a03ade1053d29bda99aa28f678836dae0669ee 100644
--- a/blimp/net/blimp_transport.h
+++ b/blimp/net/blimp_transport.h
@@ -13,6 +13,7 @@
 namespace blimp {
 
 class BlimpConnection;
+class MessagePort;
 
 // An interface which encapsulates the transport-specific code for
 // establishing network connections between the client and engine.
@@ -26,13 +27,13 @@ class BlimpTransport {
   //
   // |callback| will be invoked with the connection outcome:
   //   * net::OK if a connection is established successful, the BlimpConnection
-  //     can be taken by calling TakeConnection().
+  //     can be taken by calling TakeMessagePort().

[CJ, 2016/08/12 23:59:15]

Perhaps phrase this differently, as we are no longer getting a BlimpConnection
from TakeMessagePort(), but the associated MessagePort. 

Alternatively, you could just return a BlimpConnection wrapped around the
MessagePort you are making now and leave it as TakeConnection(). Seems like a
lot of the code does expect a connection to be made after TakeMessagePort() is
called. 

[Kevin M, 2016/08/15 17:35:09]

Fixed - rewrote the whole comment block due to awkward phrasing in general.

   //   * net::ERR_IO_PENDING will never be the outcome
   //   * Other error code indicates no connection was established.
   virtual void Connect(const net::CompletionCallback& callback) = 0;
 
-  // Returns the connection object after a successful Connect().
-  virtual std::unique_ptr<BlimpConnection> TakeConnection() = 0;
+  // Returns the MessagePort of a successfully established connection.
+  virtual std::unique_ptr<MessagePort> TakeMessagePort() = 0;
 
   // Gets transport name, e.g. "TCP", "SSL", "mock", etc.
   virtual const char* GetName() const = 0;