Add multi-process notification class.

chrome/browser/multi_process_notification.h

Index: chrome/browser/multi_process_notification.h
diff --git a/chrome/browser/multi_process_notification.h b/chrome/browser/multi_process_notification.h
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+++ b/chrome/browser/multi_process_notification.h
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+// Copyright (c) 2011 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 CHROME_BROWSER_MULTI_PROCESS_NOTIFICATION_H_
+#define CHROME_BROWSER_MULTI_PROCESS_NOTIFICATION_H_
+#pragma once
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/scoped_ptr.h"
+#include "base/task.h"
+
+class Task;
+class MessageLoop;
+
+// Platform abstraction for a notification that can be sent between processes.
+// Notifications are strings. The string will be prefixed accordingly per
+// platform (so on Mac OS X a "Happy" notification will become
+// "org.chromium.Happy").
+namespace multi_process_notification {
+
+class ListenerImpl;
+
+enum Domain {
+  // Notifications intended to be received by processes running with the
+  // same uid and same profile.
+  ProfileDomain,
+  // Notifications intended to be received by processes running with the
+  // same uid.
+  UserDomain,
+  // Notifications intended to be received by processes running on the
+  // same system.
+  SystemDomain
+};
+
+// Posts a notification |name| to |domain|.
+// Returns true if the notification was posted.
+bool Post(const std::string& name, Domain domain);
+
+// A notification listener. Will listen for a given notification and
+// call the delegate. Note that the delegate is not owned by the listener.
+class Listener {
+ public:
+  class Delegate {
+   public:
+    virtual ~Delegate();
+
+    // OnNotificationReceived is called on the thread that called Start() on the
+    // Listener associated with this delegate.
+    virtual void OnNotificationReceived(const std::string& name,
+                                        Domain domain) = 0;
+
+    // OnListenerStarted is called on the thread that called Start() on the
+    // Listener associated with this delegate. If success is false, there
+    // was an error starting the listener, and it is invalid.
+    virtual void OnListenerStarted(
+        const std::string& name, Domain domain, bool success);
+  };
+
+  class ListenerStartedTask : public Task {
+   public:
+    ListenerStartedTask(const std::string& name, Domain domain,
+        Delegate* delegate, bool success);
+    virtual ~ListenerStartedTask();
+    virtual void Run();
+
+  private:
+    std::string name_;
+    Domain domain_;
+    Delegate* delegate_;
+    bool success_;
+    DISALLOW_COPY_AND_ASSIGN(ListenerStartedTask);
+  };
+
+  class NotificationReceivedTask : public Task {
+   public:
+    NotificationReceivedTask(
+        const std::string& name, Domain domain, Delegate* delegate);
+    virtual ~NotificationReceivedTask();
+    virtual void Run();
+
+  private:
+    std::string name_;
+    Domain domain_;
+    Delegate* delegate_;
+    DISALLOW_COPY_AND_ASSIGN(NotificationReceivedTask);
+  };
+
+  Listener(const std::string& name, Domain domain, Delegate* delegate);
+
+  // A destructor is required for scoped_ptr to compile.
+  ~Listener();
+
+  // A listener is not considered valid until Start() returns true and its
+  // delegate's OnListenerStarted method is called with |success| == true
+  bool Start();
+
+ private:
+  scoped_ptr<ListenerImpl> impl_;
+
+  DISALLOW_COPY_AND_ASSIGN(Listener);
+};
+
+}  // namespace multi_process_notification
+
+#endif  // CHROME_BROWSER_MULTI_PROCESS_NOTIFICATION_H_