Make Dispatcher::AddAwakable(), etc. always set *signals_state (if signals_state is non-null).

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 175 matching lines @@
   // returns a default-constructed |HandleSignalsState|, i.e., no signals
   // satisfied or satisfiable.) Note: The state is subject to change from other
   // threads.
   HandleSignalsState GetHandleSignalsState() const;
 
   // Adds an awakable to this dispatcher, which will be woken up when this
   // object changes state to satisfy |signals| with context |context|. It will
   // also be woken up when it becomes impossible for the object to ever satisfy
   // |signals| with a suitable error status.
   //
-  // If |signals_state| is non-null, on *failure* |*signals_state| will be set
-  // to the current handle signals state (on success, it is left untouched).
+  // If |signals_state| is non-null, |*signals_state| will be set to the current
+  // handle signals state.
   //
   // Any awakable that's added must either eventually be removed (using
   // |RemoveAwakable()| or |RemoveAwakableWithContext()|, below). If an
   // awakable's |Awake()| is called (by this dispatcher) and it returns false,
   // that is equivalent to |RemoveAwakableWithContext()| being called for that
   // awakable and the context passed to |Awake()|.
   //
   // Returns:
   //  - |MOJO_RESULT_OK| if the awakable was added;
   //  - |MOJO_RESULT_ALREADY_EXISTS| if |signals| is already satisfied (if
   //    |force| is true, the awakable will still be added);
   //  - |MOJO_RESULT_INVALID_ARGUMENT| if the dispatcher has been closed; and
   //  - |MOJO_RESULT_FAILED_PRECONDITION| if it is not (or no longer) possible
   //    that |signals| will ever be satisfied.
   MojoResult AddAwakable(Awakable* awakable,
                          MojoHandleSignals signals,
                          uint64_t context,
                          HandleSignalsState* signals_state);
   // Like |AddAwakable()|, but in the |MOJO_RESULT_ALREADY_EXISTS| case still
-  // adds the awakable (|MOJO_RESULT_ALREADY_EXISTS| will still be returned and
-  // |*signals_state| will still be set if |signals_state| is non-null).
+  // adds the awakable (|MOJO_RESULT_ALREADY_EXISTS| will still be returned).
   MojoResult AddAwakableUnconditional(Awakable* awakable,
                                       MojoHandleSignals signals,
                                       uint64_t context,
                                       HandleSignalsState* signals_state);
   // Removes an awakable from this dispatcher. This will remove all instances of
   // |awakable|, regardless of context. (It is valid to call this multiple times
   // for the same |awakable| on the same object.) If |signals_state| is
   // non-null, |*signals_state| will be set to the current handle signals state.
   void RemoveAwakable(Awakable* awakable, HandleSignalsState* signals_state);
   // Like |RemoveAwakable()|, but only removes "instances" with the given
@@ skipping 289 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_