[mojo-edk] Add MojoWatch and MojoCancelWatch APIs

mojo/edk/system/awakable_list.cc

 // 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.
 
 #include "mojo/edk/system/awakable_list.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "mojo/edk/system/awakable.h"
@@ skipping 21 matching lines @@
       keep = it->awakable->Awake(MOJO_RESULT_FAILED_PRECONDITION, it->context);
 
     if (!keep) {
       --last;
       std::swap(*it, *last);
     } else {
       ++it;
     }
   }
   awakables_.erase(last, awakables_.end());
+  watchers_.NotifyForStateChange(state);
 }
 
 void AwakableList::CancelAll() {
   for (AwakeInfoList::iterator it = awakables_.begin(); it != awakables_.end();
        ++it) {
     it->awakable->Awake(MOJO_RESULT_CANCELLED, it->context);
   }
   awakables_.clear();
+  watchers_.NotifyClosed();
 }
 
 void AwakableList::Add(Awakable* awakable,
                        MojoHandleSignals signals,
                        uintptr_t context) {
   awakables_.push_back(AwakeInfo(awakable, signals, context));
 }
 
 void AwakableList::Remove(Awakable* awakable) {
   // We allow a thread to wait on the same handle multiple times simultaneously,
   // so we need to scan the entire list and remove all occurrences of |waiter|.
   auto last = awakables_.end();
   for (AwakeInfoList::iterator it = awakables_.begin(); it != last;) {
     if (it->awakable == awakable) {
       --last;
       std::swap(*it, *last);
     } else {
       ++it;
     }
   }
   awakables_.erase(last, awakables_.end());
 }
 
+MojoResult AwakableList::AddWatcher(MojoHandleSignals signals,
+                                    const Watcher::WatchCallback& callback,
+                                    uintptr_t context,
+                                    const HandleSignalsState& current_state) {
+  return watchers_.Add(signals, callback, context, current_state);
+}
+
+MojoResult AwakableList::RemoveWatcher(uintptr_t context) {
+  return watchers_.Remove(context);
+}
+
 }  // namespace edk
 }  // namespace mojo