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

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index ec4b97bad92afdfb1e432cbd41f264972016a335..a8907498963bb95e1a171a06de1d762fd26f9fb0 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -1052,6 +1052,10 @@ base::TimeTicks WebContentsImpl::GetLastActiveTime() const {
   return last_active_time_;
 }
 
+void WebContentsImpl::SetLastActiveTime(base::TimeTicks last_active_time) {
+  last_active_time_ = last_active_time;
+}
+
 void WebContentsImpl::WasShown() {
   controller_.SetActive(true);