Don't call the other wait set impl dispatcher methods under mutex either.

mojo/edk/system/dispatcher.h

 // Copyright 2013 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_EDK_SYSTEM_DISPATCHER_H_
 #define MOJO_EDK_SYSTEM_DISPATCHER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 346 matching lines @@
       MOJO_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
   virtual MojoResult GetBufferInformationImplNoLock(
       UserPointer<MojoBufferInformation> info,
       uint32_t info_num_bytes) MOJO_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
   virtual MojoResult MapBufferImplNoLock(
       uint64_t offset,
       uint64_t num_bytes,
       MojoMapBufferFlags flags,
       std::unique_ptr<platform::PlatformSharedBufferMapping>* mapping)
       MOJO_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
-  virtual MojoResult WaitSetAddImplNoLock(
+  // WARNING: Unlike the others, the following wait set methods are *not* called
+  // under |mutex_| and |is_closed_| is *not* checked. Thus any override must
+  // lock |mutex()| and check |is_closed_no_lock()| (returning
+  // |MOJO_RESULT_INVALID_ARGUMENT| if it is true).
+  virtual MojoResult WaitSetAddImpl(
       UserPointer<const MojoWaitSetAddOptions> options,
       Handle&& handle,
       MojoHandleSignals signals,
-      uint64_t cookie) MOJO_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
-  virtual MojoResult WaitSetRemoveImplNoLock(uint64_t cookie)
-      MOJO_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
-  // WARNING: Unlike the others, this method is *not* called under |mutex_| and
-  // |is_closed_| is *not* checked. Thus any override must lock |mutex()| and
-  // check |is_closed_no_lock()| (returning |MOJO_RESULT_INVALID_ARGUMENT| if it
-  // is true).
+      uint64_t cookie);
+  virtual MojoResult WaitSetRemoveImpl(uint64_t cookie);
   virtual MojoResult WaitSetWaitImpl(MojoDeadline deadline,
                                      UserPointer<uint32_t> num_results,
                                      UserPointer<MojoWaitSetResult> results,
                                      UserPointer<uint32_t> max_results);
   virtual HandleSignalsState GetHandleSignalsStateImplNoLock() const
       MOJO_SHARED_LOCKS_REQUIRED(mutex_);
   virtual MojoResult AddAwakableImplNoLock(Awakable* awakable,
                                            MojoHandleSignals signals,
                                            uint64_t context,
                                            HandleSignalsState* signals_state)
@@ skipping 106 matching lines @@
 
 // So logging macros and |DCHECK_EQ()|, etc. work.
 inline std::ostream& operator<<(std::ostream& out, Dispatcher::Type type) {
   return out << static_cast<int>(type);
 }
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_DISPATCHER_H_