Make WaitableEvent's constructor enum-based.

base/synchronization/waitable_event.h

 // Copyright (c) 2012 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 BASE_SYNCHRONIZATION_WAITABLE_EVENT_H_
 #define BASE_SYNCHRONIZATION_WAITABLE_EVENT_H_
 
 #include <stddef.h>
 
 #include "base/base_export.h"
@@ skipping 25 matching lines @@
 // WaitableEvent in conjunction with a Lock to wait for a more complex state
 // change (e.g., for an item to be added to a queue), then you should probably
 // be using a ConditionVariable instead of a WaitableEvent.
 //
 // NOTE: On Windows, this class provides a subset of the functionality afforded
 // by a Windows event object.  This is intentional.  If you are writing Windows
 // specific code and you need other features of a Windows event, then you might
 // be better off just using an Windows event directly.
 class BASE_EXPORT WaitableEvent {
  public:
+  // Indicates whether a WaitableEvent should automatically reset the event
+  // state after a single waiting thread has been released or remain signaled
+  // until Reset() is manually invoked.
+  enum class ResetPolicy { MANUAL, AUTOMATIC };
+
+  // Indicates whether a new WaitableEvent should start in a signaled state or
+  // not.
+  enum class InitialState { SIGNALED, NOT_SIGNALED };
+
+  // Constructs a WaitableEvent with policy and initial state as detailed in
+  // the above enums.
+  WaitableEvent(ResetPolicy reset_policy, InitialState initial_state);
+
   // If manual_reset is true, then to set the event state to non-signaled, a
   // consumer must call the Reset method.  If this parameter is false, then the
   // system automatically resets the event state to non-signaled after a single
   // waiting thread has been released.
+  // DEPRECATED: Use the enum-based constructor instead (full removal tracked in
+  // http://crbug.com/612843).
   WaitableEvent(bool manual_reset, bool initially_signaled);
 
 #if defined(OS_WIN)
   // Create a WaitableEvent from an Event HANDLE which has already been
   // created. This objects takes ownership of the HANDLE and will close it when
   // deleted.
   explicit WaitableEvent(win::ScopedHandle event_handle);
 #endif
 
   ~WaitableEvent();
@@ skipping 120 matching lines @@
 
   scoped_refptr<WaitableEventKernel> kernel_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(WaitableEvent);
 };
 
 }  // namespace base
 
 #endif  // BASE_SYNCHRONIZATION_WAITABLE_EVENT_H_