Don't post tasks from RulesRegistry c-tor

extensions/common/one_shot_event.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 EXTENSIONS_COMMON_ONE_SHOT_EVENT_H_
 #define EXTENSIONS_COMMON_ONE_SHOT_EVENT_H_
 
 #include <vector>
 
 #include "base/callback_forward.h"
@@ skipping 17 matching lines @@
 // is signaled.  If the OneShotEvent is destroyed before it's
 // signaled, the delayed closures are destroyed without being run.
 //
 // This class is similar to a WaitableEvent combined with several
 // WaitableEventWatchers, but using it is simpler.
 //
 // This class is not thread-safe, and must be used from a single thread.
 class OneShotEvent {
  public:
   OneShotEvent();
+  // Use the following constructor to create an already signaled event. This is
+  // useful if you construct the event on a different thread from where it is
+  // used, in which case it is not possible to call Signal() just after
+  // construction.
+  explicit OneShotEvent(bool signaled);
   ~OneShotEvent();
 
   // True if Signal has been called.  This function is mostly for
   // migrating old code; usually calling Post() unconditionally will
   // result in more readable code.
   bool is_signaled() const {
     DCHECK(thread_checker_.CalledOnValidThread());
     return signaled_;
   }
 
@@ skipping 41 matching lines @@
   // Optimization note: We could reduce the size of this class to a
   // single pointer by storing |signaled_| in the low bit of a
   // pointer, and storing the size and capacity of the array (if any)
   // on the far end of the pointer.
   mutable std::vector<TaskInfo> tasks_;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_ONE_SHOT_EVENT_H_