[PlzNavigate] Add load flags for prefetch navigations

chrome/browser/prerender/prerender_resource_throttle.h

Index: chrome/browser/prerender/prerender_resource_throttle.h
diff --git a/chrome/browser/prerender/prerender_resource_throttle.h b/chrome/browser/prerender/prerender_resource_throttle.h
index f0143ea0e8a9e8036d9e12a0c353aa752ca108f7..d53844fdf5ef112781f6c9300abdd87acced0ad5 100644
--- a/chrome/browser/prerender/prerender_resource_throttle.h
+++ b/chrome/browser/prerender/prerender_resource_throttle.h
@@ -10,6 +10,7 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "chrome/browser/prerender/prerender_manager.h"
 #include "content/public/browser/resource_request_info.h"
 #include "content/public/browser/resource_throttle.h"
 #include "content/public/common/resource_type.h"
@@ -83,7 +84,10 @@ class PrerenderResourceThrottle
       const content::ResourceRequestInfo::WebContentsGetter&
           web_contents_getter);
 
+  void set_prerender_mode(PrerenderMode mode) { prerender_mode_ = mode; }
+
   net::URLRequest* request_;
+  PrerenderMode prerender_mode_;
 
   scoped_refptr<PrerenderThrottleInfo> prerender_throttle_info_;