Implementation and fixes for Blimp client/engine E2E communication.

blimp/net/blimp_connection.h

Index: blimp/net/blimp_connection.h
diff --git a/blimp/net/blimp_connection.h b/blimp/net/blimp_connection.h
index 36128af42300df09ca881ad0309ef842fad20cff..ea729595cf9fe2aefa91d99f76bba597d9119664 100644
--- a/blimp/net/blimp_connection.h
+++ b/blimp/net/blimp_connection.h
@@ -7,27 +7,36 @@
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/observer_list.h"
 #include "blimp/net/blimp_net_export.h"
+#include "blimp/net/connection_error_observer.h"
 
 namespace blimp {
 
 class BlimpMessageProcessor;
 class BlimpMessagePump;
-class ConnectionErrorObserver;
 class PacketReader;
 class PacketWriter;
 
 // Encapsulates the state and logic used to exchange BlimpMessages over
 // a network connection.
-class BLIMP_NET_EXPORT BlimpConnection {
+class BLIMP_NET_EXPORT BlimpConnection : public ConnectionErrorObserver {
  public:
   BlimpConnection(scoped_ptr<PacketReader> reader,
                   scoped_ptr<PacketWriter> writer);
 
-  virtual ~BlimpConnection();
+  ~BlimpConnection() override;
 
-  // Lets |observer| know when the network connection encounters an error.
-  virtual void SetConnectionErrorObserver(ConnectionErrorObserver* observer);
+  // Adds |observer| to the connection's error observer list.
+  virtual void AddConnectionErrorObserver(ConnectionErrorObserver* observer);
+
+  // Removes all error observers from the observer list.
+  // Should be used to suppress error output in cases where an expected error
+  // code should be suppressed, e.g. on graceful disconnects.
+  virtual void ClearConnectionErrorObservers();

[haibinlu, 2016/01/04 19:45:45]

per offline discussion, this can be removed.

[Kevin M, 2016/01/04 20:42:13]

Removed this and relocated error observers to the end of the field list, so that
the observers are deleted before the socket objects, effectively suppressing
errors.

+
+  // Removes |observer| from the connection's error observer list.
+  virtual void RemoveConnectionErrorObserver(ConnectionErrorObserver* observer);
 
   // Sets the processor which will take incoming messages for this connection.
   // Can be set multiple times, but previously set processors are discarded.
@@ -37,10 +46,14 @@ class BLIMP_NET_EXPORT BlimpConnection {
   // Gets a processor for BrowserSession->BlimpConnection message routing.
   virtual BlimpMessageProcessor* GetOutgoingMessageProcessor();
 
+  // ConnectionErrorObserver implementation.
+  void OnConnectionError(int error) override;

[haibinlu, 2016/01/04 19:45:45]

move this to private

[Kevin M, 2016/01/04 20:42:13]

Done.

+
  protected:
   BlimpConnection();
 
  private:
+  base::ObserverList<ConnectionErrorObserver> error_observers_;
   scoped_ptr<PacketReader> reader_;
   scoped_ptr<BlimpMessagePump> message_pump_;
   scoped_ptr<PacketWriter> writer_;