Add different behavior to AwakableList for "persistent" vs "one-shot" awakables.

mojo/edk/system/wait_set_dispatcher.h

 // Copyright 2016 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_WAIT_SET_DISPATCHER_H_
 #define MOJO_EDK_SYSTEM_WAIT_SET_DISPATCHER_H_
 
 #include <map>
 #include <memory>
 
@@ skipping 44 matching lines @@
     return AdoptRef(new WaitSetDispatcher());
   }
 
   // |Dispatcher| public methods:
   Type GetType() const override;
   bool SupportsEntrypointClass(EntrypointClass entrypoint_class) const override;
 
  private:
   // Represents an entry in the wait set.
   struct Entry {
-    enum class TriggerState {
-      NOT_TRIGGERED,
-      POSSIBLY_SATISFIED,
-      NEVER_SATISFIABLE,
-      CLOSED
-    };
+    enum class TriggerState { NOT_TRIGGERED, SATISFIED, UNSATISFIABLE, CLOSED };
 
     Entry(MojoHandleSignals signals, uint64_t cookie);
     ~Entry();
 
     const MojoHandleSignals signals;
     const uint64_t cookie;
     // There are two cases when |dispatcher| is null for an |Entry| in
     // |WaitSetDispatcher::entries_|:
     //   - The wait set was closed in the middle of |WaitSetAddImpl()|;
     //     |entries_| will be cleared out on closing, but |WaitSetAddImpl()|
@@ skipping 25 matching lines @@
                             util::RefPtr<Dispatcher>&& dispatcher,
                             MojoHandleSignals signals,
                             uint64_t cookie) override;
   MojoResult WaitSetRemoveImpl(uint64_t cookie) override;
   MojoResult WaitSetWaitImpl(MojoDeadline deadline,
                              UserPointer<uint32_t> num_results,
                              UserPointer<MojoWaitSetResult> results,
                              UserPointer<uint32_t> max_results) override;
 
   // |Awakable| implementation:
-  bool Awake(uint64_t context,
+  void Awake(uint64_t context,
              AwakeReason reason,
              const HandleSignalsState& signals_state) override;
 
   void AddPossiblyTriggeredNoLock(Entry* entry,
                                   Entry::TriggerState new_trigger_state)
       MOJO_EXCLUSIVE_LOCKS_REQUIRED(mutex());
   void RemovePossiblyTriggeredNoLock(Entry* entry)
       MOJO_EXCLUSIVE_LOCKS_REQUIRED(mutex());
 
   // Set when in the middle of a wait set operation (i.e., |WaitSet...Impl()|)
@@ skipping 13 matching lines @@
   // Size of the above list.
   size_t possibly_triggered_count_ MOJO_GUARDED_BY(mutex()) = 0u;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(WaitSetDispatcher);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_WAIT_SET_DISPATCHER_H_