Mojo C++ bindings: Add a SINGLE_INTERFACE_WITH_SYNC_REQUESTS mode for MultiplexRouter.

mojo/public/cpp/bindings/lib/multiplex_router.h

 // 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.
 
 #ifndef MOJO_PUBLIC_CPP_BINDINGS_LIB_MULTIPLEX_ROUTER_H_
 #define MOJO_PUBLIC_CPP_BINDINGS_LIB_MULTIPLEX_ROUTER_H_
 
 #include <stdint.h>
 
 #include <deque>
@@ skipping 45 matching lines @@
       public AssociatedGroupController,
       public PipeControlMessageHandlerDelegate {
  public:
   enum Config {
     // There is only the master interface running on this router. Please note
     // that because of interface versioning, the other side of the message pipe
     // may use a newer master interface definition which passes associated
     // interfaces. In that case, this router may still receive pipe control
     // messages or messages targetting associated interfaces.
     SINGLE_INTERFACE,
+    // Similar to the mode above, there is only the master interface running on
+    // this router. Besides, the master interface has sync methods.
+    SINGLE_INTERFACE_WITH_SYNC_METHODS,
     // There may be associated interfaces running on this router.
     MULTI_INTERFACE
   };
 
   // If |set_interface_id_namespace_bit| is true, the interface IDs generated by
   // this router will have the highest bit set.
   MultiplexRouter(ScopedMessagePipeHandle message_pipe,
                   Config config,
                   bool set_interface_id_namespace_bit,
                   scoped_refptr<base::SingleThreadTaskRunner> runner);
@@ skipping 151 matching lines @@
 
   // Owned by |filters_| below.
   MessageHeaderValidator* header_validator_;
 
   FilterChain filters_;
   Connector connector_;
 
   base::ThreadChecker thread_checker_;
 
   // Protects the following members.
-  // Sets to nullptr in Config::SINGLE_INTERFACE mode.
+  // Sets to nullptr in Config::SINGLE_INTERFACE* mode.
   std::unique_ptr<base::Lock> lock_;
   PipeControlMessageHandler control_message_handler_;
   PipeControlMessageProxy control_message_proxy_;
 
   std::map<InterfaceId, scoped_refptr<InterfaceEndpoint>> endpoints_;
   uint32_t next_interface_id_value_;
 
   std::deque<std::unique_ptr<Task>> tasks_;
   // It refers to tasks in |tasks_| and doesn't own any of them.
   std::map<InterfaceId, std::deque<Task*>> sync_message_tasks_;
 
   bool posted_to_process_tasks_;
   scoped_refptr<base::SingleThreadTaskRunner> posted_to_task_runner_;
 
   bool encountered_error_;
 
   bool paused_;
 
   bool testing_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(MultiplexRouter);
 };
 
 }  // namespace internal
 }  // namespace mojo
 
 #endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_MULTIPLEX_ROUTER_H_