IdentityLaunchWebAuthFlowFunction shouldn't be able to send response twice.

chrome/browser/extensions/api/identity/identity_api.cc

 // Copyright (c) 2012 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 "chrome/browser/extensions/api/identity/identity_api.h"
 
 #include <set>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 925 matching lines @@
       break;
     case WebAuthFlow::LOAD_FAILED:
       error_ = identity_constants::kPageLoadFailure;
       break;
     default:
       NOTREACHED() << "Unexpected error from web auth flow: " << failure;
       error_ = identity_constants::kInvalidRedirect;
       break;
   }
   SendResponse(false);
   Release();  // Balanced in RunAsync.

[Michael Courage, 2015/01/08 22:45:27]

Would we not also want to detach here as well?

 }
 
 void IdentityLaunchWebAuthFlowFunction::OnAuthFlowURLChange(
     const GURL& redirect_url) {
   if (redirect_url.GetWithEmptyPath() == final_url_prefix_) {
     SetResult(new base::StringValue(redirect_url.spec()));
     SendResponse(true);
+    if (auth_flow_)
+      auth_flow_.release()->DetachDelegateAndDelete();
     Release();  // Balanced in RunAsync.
   }
 }
 
 }  // namespace extensions