Update from https://crrev.com/304121

net/http/http_auth_handler.cc

Index: net/http/http_auth_handler.cc
diff --git a/net/http/http_auth_handler.cc b/net/http/http_auth_handler.cc
index 7369ea5425fd961e163839aed492bbe4db22650a..4de2226caa24c1b0d1c571e72d93e7a60429ecec 100644
--- a/net/http/http_auth_handler.cc
+++ b/net/http/http_auth_handler.cc
@@ -64,7 +64,7 @@ NetLog::EventType EventTypeFromAuthTarget(HttpAuth::Target target) {
 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);
@@ -96,8 +96,8 @@ bool HttpAuthHandler::AllowsExplicitCredentials() {
 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() {