Add KeepAliveStateObserver, add the Restart option

chrome/browser/lifetime/scoped_keep_alive.h

Index: chrome/browser/lifetime/scoped_keep_alive.h
diff --git a/chrome/browser/lifetime/scoped_keep_alive.h b/chrome/browser/lifetime/scoped_keep_alive.h
index 8e73723a99aeb8ed5272cfa7f1f7c59d3530e7eb..bff52a16b9787f1f56878c5d02b7fab306fbba35 100644
--- a/chrome/browser/lifetime/scoped_keep_alive.h
+++ b/chrome/browser/lifetime/scoped_keep_alive.h
@@ -8,16 +8,19 @@
 #include "base/macros.h"
 
 enum class KeepAliveOrigin;
+enum class KeepAliveRestartOption;
 
 // Registers with KeepAliveRegistry on creation and unregisters them
 // on destruction. Use these objects with a scoped_ptr for easy management.
 class ScopedKeepAlive {
  public:
-  explicit ScopedKeepAlive(KeepAliveOrigin origin);
+  explicit ScopedKeepAlive(KeepAliveOrigin origin,

[sky, 2016/02/26 22:13:25]

nit: no explicit.

[dgn, 2016/03/09 16:35:32]

Done.

+                           KeepAliveRestartOption restart);
   ~ScopedKeepAlive();
 
  private:
   const KeepAliveOrigin origin_;
+  const KeepAliveRestartOption restart_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedKeepAlive);
 };