[Session restore] Add MRU logic to loading of background pages.

content/browser/web_contents/web_contents_impl.h

Index: content/browser/web_contents/web_contents_impl.h
diff --git a/content/browser/web_contents/web_contents_impl.h b/content/browser/web_contents/web_contents_impl.h
index e5e473eaac0630e11064b6e8959fded268a94881..e285fadd0e377154623dfaabd4d3543c737be9ba 100644
--- a/content/browser/web_contents/web_contents_impl.h
+++ b/content/browser/web_contents/web_contents_impl.h
@@ -276,6 +276,7 @@ class CONTENT_EXPORT WebContentsImpl
   bool IsBeingDestroyed() const override;
   void NotifyNavigationStateChanged(InvalidateTypes changed_flags) override;
   base::TimeTicks GetLastActiveTime() const override;
+  void SetLastActiveTime(base::TimeTicks time) override;
   void WasShown() override;
   void WasHidden() override;
   bool NeedToFireBeforeUnload() override;