Incorporate BlobChannel into Blimp image encode/decode pipeline.

blimp/net/browser_connection_handler.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "blimp/net/browser_connection_handler.h"
 
 #include "base/logging.h"
 #include "base/macros.h"
 #include "blimp/net/blimp_connection.h"
 #include "blimp/net/blimp_message_checkpointer.h"
@@ skipping 45 matching lines @@
   output_buffer_->SetOutputProcessor(
       connection_->GetOutgoingMessageProcessor());
   connection_->AddConnectionErrorObserver(this);
 }
 
 void BrowserConnectionHandler::OnConnectionError(int error) {
   DropCurrentConnection();
 }
 
 void BrowserConnectionHandler::DropCurrentConnection() {
-  DCHECK(connection_);
+  if (!connection_) {
+    return;
+  }
+
   output_buffer_->SetOutputProcessor(nullptr);
   connection_.reset();
 }
 
 }  // namespace blimp