Add KeepAliveStateObserver, add the Restart option

chrome/browser/lifetime/keep_alive_registry.h

Index: chrome/browser/lifetime/keep_alive_registry.h
diff --git a/chrome/browser/lifetime/keep_alive_registry.h b/chrome/browser/lifetime/keep_alive_registry.h
index 321e747014f8224568b6d429328932e388b5d52c..09053912c2e65e38caf0e608d5b1f773cd7b352a 100644
--- a/chrome/browser/lifetime/keep_alive_registry.h
+++ b/chrome/browser/lifetime/keep_alive_registry.h
@@ -11,11 +11,14 @@
 #include "base/memory/singleton.h"
 
 struct KeepAliveOptions;
+class KeepAliveStateObserver;
 
 class KeepAliveRegistry {
  public:
   static KeepAliveRegistry* GetInstance();
 
+  void SetObserver(KeepAliveStateObserver* observer);
+
  private:
   friend struct base::DefaultSingletonTraits<KeepAliveRegistry>;
   // Friend to be able to use Register/Unregister
@@ -28,7 +31,14 @@ class KeepAliveRegistry {
   void Register(const KeepAliveOptions* options);
   void Unregister(const KeepAliveOptions* options);
 
+  void DumpCurrentState() const;
+  KeepAliveOptions ComputeCurrentState() const;
+  void NotifyOfStateDifferences(const KeepAliveOptions& previous_state) const;
+
+  KeepAliveStateObserver* observer_;
+
   std::multiset<const KeepAliveOptions*> registered_keep_alives_;
+  std::multiset<const KeepAliveOptions*> restart_allowed_keep_alives_;
 
   DISALLOW_COPY_AND_ASSIGN(KeepAliveRegistry);
 };