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 39048f45d766b0399c1a672349da80d8f28659ec..939ebe28b6455ef305f5060b6330fa78b24312bd 100644
--- a/chrome/browser/lifetime/keep_alive_types.h
+++ b/chrome/browser/lifetime/keep_alive_types.h
@@ -7,11 +7,17 @@
 
 #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.
 namespace keep_alive {
 
+// Refers to the what the KeepAlive's lifetime is tied to, to help debugging.
 enum class Origin {
   // c/b/background
   BACKGROUND_MODE_MANAGER,
+  BACKGROUND_MODE_MANAGER_STARTUP,
 
   // c/b/ui
   APP_LIST_SERVICE_VIEWS,
@@ -22,10 +28,15 @@ enum class Origin {
   USER_MANAGER_VIEW
 };
 
-}  // namespace keep_alive
+// Restart: Allow Chrome to restart when all the registered KeepAlives allow
+// restarts
+enum class RestartOption { DISABLED, ENABLED };
 
 #ifndef NDEBUG
-std::ostream& operator<<(std::ostream& out, const keep_alive::Origin& origin);
+std::ostream& operator<<(std::ostream& out, const Origin& origin);
+std::ostream& operator<<(std::ostream& out, const RestartOption& restart);
 #endif  // ndef NDEBUG
 
+}  // namespace keep_alive
+
 #endif  // CHROME_BROWSER_LIFETIME_KEEP_ALIVE_TYPES_H_