Navigation transitions: Block first response until after transitions have run.

content/browser/loader/cross_site_resource_handler.h

Index: content/browser/loader/cross_site_resource_handler.h
diff --git a/content/browser/loader/cross_site_resource_handler.h b/content/browser/loader/cross_site_resource_handler.h
index 257af02c01be003f8ff93c14e20ec99772d8b225..f51f6163be25361144596845cbd490d0b27ebe65 100644
--- a/content/browser/loader/cross_site_resource_handler.h
+++ b/content/browser/loader/cross_site_resource_handler.h
@@ -49,6 +49,14 @@ class CrossSiteResourceHandler : public LayeredResourceHandler {
   CONTENT_EXPORT static void SetLeakRequestsForTesting(
       bool leak_requests_for_testing);
 
+  // Navigations are deferred at OnResponseStarted to parse out any navigation
+  // transition link headers, and give the navigation transition (if it exists)
+  // a chance to run.
+  void ResumeResponseDeferredAtStart(int request_id);
+
+  // Returns whether the handler is deferred.
+  bool did_defer_for_testing() const { return did_defer_; }
+
  private:
   // Prepare to render the cross-site response in a new RenderViewHost, by
   // telling the old RenderViewHost to run its onunload handler.
@@ -61,6 +69,12 @@ class CrossSiteResourceHandler : public LayeredResourceHandler {
                                      ResourceResponse* response,
                                      bool* defer);
 
+  bool OnNavigationTransitionResponseStarted(ResourceResponse* response,
+                                             bool* defer);
+
+  bool OnNormalResponseStarted(ResourceResponse* response,
+                               bool* defer);
+
   void ResumeOrTransfer(bool is_transfer);
   void ResumeIfDeferred();