Mojo: Armed Watchers

mojo/edk/system/watcher_set.h

Index: mojo/edk/system/watcher_set.h
diff --git a/mojo/edk/system/watcher_set.h b/mojo/edk/system/watcher_set.h
index 8ae54a1b35270faf5d3fe8fc3b753764623362c1..9beaf98091260eba09abdc43fbbcb070dfdf621f 100644
--- a/mojo/edk/system/watcher_set.h
+++ b/mojo/edk/system/watcher_set.h
@@ -5,7 +5,7 @@
 #ifndef MOJO_EDK_SYSTEM_WATCHER_SET_H_
 #define MOJO_EDK_SYSTEM_WATCHER_SET_H_
 
-#include <unordered_map>
+#include <map>
 
 #include "base/callback.h"
 #include "base/macros.h"
@@ -24,26 +24,29 @@ class WatcherSet {
   WatcherSet();
   ~WatcherSet();
 
-  // Notifies all Watchers of a state change.
-  void NotifyForStateChange(const HandleSignalsState& state);
+  // Notifies all Watchers of the handle's current signals state.
+  void NotifyState(const HandleSignalsState& state);
 
   // Notifies all Watchers that their watched handle has been closed.
   void NotifyClosed();
 
   // Adds a new watcher to watch for signals in |signals| to be satisfied or
-  // unsatisfiable. |current_state| is the current signals state of the
-  // handle being watched.
+  // unsatisfiable.
   MojoResult Add(MojoHandleSignals signals,
                  const Watcher::WatchCallback& callback,
                  uintptr_t context,
                  const HandleSignalsState& current_state);
 
+  // Attempts to arm a watcher. May fail depending on |current_state|. See
+  // public |MojoArmWatcher()| documentation for error code details.
+  MojoResult Arm(uintptr_t context, const HandleSignalsState& current_state);
+
   // Removes a watcher from the set.
   MojoResult Remove(uintptr_t context);
 
  private:
   // A map of watchers keyed on context value.
-  std::unordered_map<uintptr_t, scoped_refptr<Watcher>> watchers_;
+  std::map<uintptr_t, scoped_refptr<Watcher>> watchers_;
 
   DISALLOW_COPY_AND_ASSIGN(WatcherSet);
 };