This defers starting background extension page RenderViews

chrome/browser/extensions/extension_process_manager.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_EXTENSION_PROCESS_MANAGER_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_PROCESS_MANAGER_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 116 matching lines @@
 
   // Tracks network requests for a given RenderViewHost, used to know
   // when network activity is idle for lazy background pages.
   void OnNetworkRequestStarted(content::RenderViewHost* render_view_host);
   void OnNetworkRequestDone(content::RenderViewHost* render_view_host);
 
   // Prevents |extension|'s background page from being closed and sends the
   // onSuspendCanceled() event to it.
   void CancelSuspend(const extensions::Extension* extension);
 
+  // If |defer| is true background host creation is to be deferred until this is
+  // called again with |defer| set to false, at which point all deferred
+  // background hosts will be created.  Defaults to false.
+  void DeferBackgroundHostCreation(bool defer);
+
  protected:
   explicit ExtensionProcessManager(Profile* profile);
 
   // Called just after |host| is created so it can be registered in our lists.
   void OnExtensionHostCreated(extensions::ExtensionHost* host,
                               bool is_background);
 
   // Called on browser shutdown to close our extension hosts.
   void CloseBackgroundHosts();
 
@@ skipping 45 matching lines @@
 
   // Potentially registers a RenderViewHost, if it is associated with an
   // extension. Does nothing if this is not an extension renderer.
   void RegisterRenderViewHost(content::RenderViewHost* render_view_host);
 
   // Clears background page data for this extension.
   void ClearBackgroundPageData(const std::string& extension_id);
 
   // Returns true if loading background pages should be deferred. This is
   // true if there are no browser windows open and the browser process was
-  // started to show the app launcher.
+  // started to show the app launcher, or if DeferBackgroundHostCreation was
+  // called with true, or if the profile is not yet valid.
   bool DeferLoadingBackgroundHosts() const;
 
   void OnDevToolsStateChanged(content::DevToolsAgentHost*, bool attached);
 
   // Contains all active extension-related RenderViewHost instances for all
   // extensions. We also keep a cache of the host's view type, because that
   // information is not accessible at registration/deregistration time.
   ExtensionRenderViews all_extension_views_;
 
   BackgroundPageDataMap background_page_data_;
 
   // The time to delay between an extension becoming idle and
   // sending a ShouldSuspend message; read from command-line switch.
   base::TimeDelta event_page_idle_time_;
 
   // The time to delay between sending a ShouldSuspend message and
   // sending a Suspend message; read from command-line switch.
   base::TimeDelta event_page_suspending_time_;
 
+  // If true, then creation of background hosts is suspended.
+  bool defer_background_host_creation_;
+
   base::WeakPtrFactory<ExtensionProcessManager> weak_ptr_factory_;
 
   base::Callback<void(content::DevToolsAgentHost*, bool)> devtools_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionProcessManager);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PROCESS_MANAGER_H_