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

content/browser/renderer_host/render_widget_helper.h

Index: content/browser/renderer_host/render_widget_helper.h
diff --git a/content/browser/renderer_host/render_widget_helper.h b/content/browser/renderer_host/render_widget_helper.h
index af5c6612b5edfcab4ff382de9445bfe1b23bed00..e424c764df73ffb5dab6ee02962a5de72a0a2476 100644
--- a/content/browser/renderer_host/render_widget_helper.h
+++ b/content/browser/renderer_host/render_widget_helper.h
@@ -125,10 +125,11 @@ class RenderWidgetHelper
 
   // UI THREAD ONLY -----------------------------------------------------------
 
-  // These three functions provide the backend implementation of the
+  // These four functions provide the backend implementation of the
   // corresponding functions in RenderProcessHost. See those declarations
   // for documentation.
   void ResumeDeferredNavigation(const GlobalRequestID& request_id);
+  void ResumeResponseDeferredAtStart(const GlobalRequestID& request_id);
   bool WaitForBackingStoreMsg(int render_widget_id,
                               const base::TimeDelta& max_delay,
                               IPC::Message* msg);
@@ -219,6 +220,10 @@ class RenderWidgetHelper
   // stack without transferring it to a new renderer process.
   void OnResumeDeferredNavigation(const GlobalRequestID& request_id);
 
+  // Called on the IO thread to resume a navigation paused immediately after
+  // receiving response headers.
+  void OnResumeResponseDeferredAtStart(const GlobalRequestID& request_id);
+
 #if defined(OS_POSIX)
   // Called on destruction to release all allocated transport DIBs
   void ClearAllocatedDIBs();