This defers starting background extension page RenderViews

chrome/browser/extensions/extension_process_manager.h

Index: chrome/browser/extensions/extension_process_manager.h
diff --git a/chrome/browser/extensions/extension_process_manager.h b/chrome/browser/extensions/extension_process_manager.h
index 12fdf4a9c6358a1bb9cab6113f78680fd2189a79..9230f911abda05f73133c2add3fe75f76ba72dd8 100644
--- a/chrome/browser/extensions/extension_process_manager.h
+++ b/chrome/browser/extensions/extension_process_manager.h
@@ -134,6 +134,14 @@ class ExtensionProcessManager : public content::NotificationObserver {
   // onSuspendCanceled() event to it.
   void CancelSuspend(const extensions::Extension* extension);
 
+  // Determines whether ExtensionHost creation for background hosts is to be
+  // deferred until CreateDeferredBackgroundHosts is called.  If |defer| is
+  // true, then it will be deferred.
+  void DeferBackgroundHostCreation(bool defer);
+
+  // Cause any background ExtensionHosts that were deferred to be created.
+  void CreateDeferredBackgroundHosts();
+
  protected:
   explicit ExtensionProcessManager(Profile* profile);
 
@@ -219,6 +227,10 @@ class ExtensionProcessManager : public content::NotificationObserver {
   // sending a Suspend message; read from command-line switch.
   base::TimeDelta event_page_suspending_time_;
 
+  // If true, then creation of background hosts is suspended until
+  // CreateDeferredBackgroundHosts is called.
+  bool defer_background_host_creation_;
+
   base::WeakPtrFactory<ExtensionProcessManager> weak_ptr_factory_;
 
   base::Callback<void(content::DevToolsAgentHost*, bool)> devtools_callback_;