Update from https://crrev.com/304121

net/http/http_auth_handler.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 "net/http/http_auth_handler.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "net/base/net_errors.h"
@@ skipping 46 matching lines @@
       NOTREACHED();
       return NetLog::TYPE_CANCELLED;
   }
 }
 
 }  // namespace
 
 int HttpAuthHandler::GenerateAuthToken(
     const AuthCredentials* credentials, const HttpRequestInfo* request,
     const CompletionCallback& callback, std::string* auth_token) {
-  // TODO(cbentzel): Enforce non-NULL callback after cleaning up SocketStream.
+  DCHECK(!callback.is_null());
   DCHECK(request);
   DCHECK(credentials != NULL || AllowsDefaultCredentials());
   DCHECK(auth_token != NULL);
   DCHECK(callback_.is_null());
   callback_ = callback;
   net_log_.BeginEvent(EventTypeFromAuthTarget(target_));
   int rv = GenerateAuthTokenImpl(
       credentials, request,
       base::Bind(&HttpAuthHandler::OnGenerateAuthTokenComplete,
                  base::Unretained(this)),
@@ skipping 11 matching lines @@
   return false;
 }
 
 bool HttpAuthHandler::AllowsExplicitCredentials() {
   return true;
 }
 
 void HttpAuthHandler::OnGenerateAuthTokenComplete(int rv) {
   CompletionCallback callback = callback_;
   FinishGenerateAuthToken();
-  if (!callback.is_null())
-    callback.Run(rv);
+  DCHECK(!callback.is_null());
+  callback.Run(rv);
 }
 
 void HttpAuthHandler::FinishGenerateAuthToken() {
   // TOOD(cbentzel): Should this be done in OK case only?
   net_log_.EndEvent(EventTypeFromAuthTarget(target_));
   callback_.Reset();
 }
 
 }  // namespace net