Add KeepAliveStateObserver, add the Restart option

chrome/browser/lifetime/keep_alive_types.h

Index: chrome/browser/lifetime/keep_alive_types.h
diff --git a/chrome/browser/lifetime/keep_alive_types.h b/chrome/browser/lifetime/keep_alive_types.h
index 0fc846649f4311c70407f0062eb489bf5d4e6399..e41d5c1ce523e9e58d436aa7ee866f654b51dc07 100644
--- a/chrome/browser/lifetime/keep_alive_types.h
+++ b/chrome/browser/lifetime/keep_alive_types.h
@@ -7,9 +7,16 @@
 
 #include <ostream>
 
+// Types here are used to register KeepAlives.
+// They Give indications about which kind of optimizations are allowed during
+// the KeepAlive's lifetime. This allows to have more info about the state of
+// the browser to optimize the resource consumption.
+
+// Refers to the what the KeepAlive's lifetime is tied to, to help debugging.
 enum class KeepAliveOrigin {
   // c/b/background
   BACKGROUND_MODE_MANAGER,
+  BACKGROUND_MODE_MANAGER_STARTUP,
 
   // c/b/ui
   APP_LIST_SERVICE_VIEWS,
@@ -20,8 +27,14 @@ enum class KeepAliveOrigin {
   USER_MANAGER_VIEW
 };
 
+// Restart: Allow Chrome to restart when all the registered KeepAlives allow
+// restarts
+enum class KeepAliveRestartOption { DISABLED, ENABLED };
+
 #ifndef NDEBUG
 std::ostream& operator<<(std::ostream& out, const KeepAliveOrigin& origin);
+std::ostream& operator<<(std::ostream& out,
+                         const KeepAliveRestartOption& restart);
 #endif  // ndef NDEBUG
 
 #endif  // CHROME_BROWSER_LIFETIME_KEEP_ALIVE_TYPES_H_