Replace BrowserProces::AddRefModule/RemoveModule by ScopedKeepAlive

chrome/browser/lifetime/keep_alive_registry.h

 // Copyright 2016 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_LIFETIME_KEEP_ALIVE_REGISTRY_H_
 #define CHROME_BROWSER_LIFETIME_KEEP_ALIVE_REGISTRY_H_
 
 #include <map>
 
 #include "base/macros.h"
 #include "base/memory/singleton.h"
 #include "base/observer_list.h"
 
 enum class KeepAliveOrigin;
 enum class KeepAliveRestartOption;
 class KeepAliveStateObserver;
 
+// Centralized registry that objects in the browser can use to
+// express their requirements wrt the lifetime of the browser.
+// Observers registered with it can then react as those requirements
+// change.
+// In particular, this is how the browser process knows when to stop
+// or stay alive.
+// Note: BrowserProcessImpl registers to react on changes.
+// TestingBrowserProcess does not do it, meaning that the shutdown
+// sequence does not happen during unit tests.
 class KeepAliveRegistry {
  public:
   static KeepAliveRegistry* GetInstance();
 
   // Methods to query the state of the registry.
-  // TODO(dgn): This currently does not give a complete picture. It has no
-  // information about the many places that rely on AddRefModule to keep the
-  // browser alive. Tracked by https://crbug.com/587926
   bool IsKeepingAlive() const;
   bool IsRestartAllowed() const;
+  bool IsOriginRegistered(KeepAliveOrigin origin) const;
 
   void AddObserver(KeepAliveStateObserver* observer);
   void RemoveObserver(KeepAliveStateObserver* observer);
 
  private:
   friend struct base::DefaultSingletonTraits<KeepAliveRegistry>;
   // Friend to be able to use Register/Unregister
   friend class ScopedKeepAlive;
   friend std::ostream& operator<<(std::ostream& out,
                                   const KeepAliveRegistry& registry);
 
   KeepAliveRegistry();
   ~KeepAliveRegistry();
 
   // Add/Remove entries. Do not use directly, use ScopedKeepAlive instead.
   void Register(KeepAliveOrigin origin, KeepAliveRestartOption restart);
   void Unregister(KeepAliveOrigin origin, KeepAliveRestartOption restart);
 
   // Methods called when a specific aspect of the state of the registry changes.
-  void OnKeepingAliveChanged(bool new_keeping_alive);
+  void OnKeepAliveStateChanged(bool new_keeping_alive);
   void OnRestartAllowedChanged(bool new_restart_allowed);
 
   // Tracks the registered KeepAlives, storing the origin and the number of
   // registered KeepAlives for each.
   std::map<KeepAliveOrigin, int> registered_keep_alives_;
 
   // Total number of registered KeepAlives
   int registered_count_;
 
   // Number of registered keep alives that have KeepAliveRestartOption::ENABLED.
   int restart_allowed_count_;
 
   base::ObserverList<KeepAliveStateObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(KeepAliveRegistry);
 };
 
 #ifndef NDEBUG
 std::ostream& operator<<(std::ostream& out, const KeepAliveRegistry& registry);
 #endif  // ndef NDEBUG
 
 #endif  // CHROME_BROWSER_LIFETIME_KEEP_ALIVE_REGISTRY_H_