Refactor code that defers extension background page loading

extensions/browser/process_manager.h

Index: extensions/browser/process_manager.h
diff --git a/extensions/browser/process_manager.h b/extensions/browser/process_manager.h
index 664c9420fde504a05d071e6de9a9a232722b57fa..c4d8e910d0a005f4246f3163ef30e0c60096541e 100644
--- a/extensions/browser/process_manager.h
+++ b/extensions/browser/process_manager.h
@@ -35,6 +35,24 @@ class Extension;
 class ExtensionHost;
 class ProcessManagerObserver;
 
+// Customization of ProcessManager from the extension system embedder.
+class ProcessManagerDelegate {

[Yoyo Zhou, 2014/07/15 02:13:22]

Probably it's best to put this in a separate header file.

[James Cook, 2014/07/15 17:02:52]

Done.

+ public:
+  virtual ~ProcessManagerDelegate() {}
+
+  // Returns true if the embedder allows background pages for the given
+  // |context|.
+  virtual bool IsBackgroundPageAllowed(
+      content::BrowserContext* context) const = 0;
+
+  // Returns true if the embedder wishes to defer starting up the renderers for
+  // extension background pages. If the embedder returns true it must call
+  // ProcessManager::MaybeCreateStartupBackgroundHosts() when it is ready. See
+  // ChromeProcessManagerDelegate for examples of how this is useful.
+  virtual bool DeferCreatingStartupBackgroundHosts(
+      content::BrowserContext* context) const = 0;
+};
+
 // Manages dynamic state of running Chromium extensions. There is one instance
 // of this class per Profile. OTR Profiles have a separate instance that keeps
 // track of split-mode extensions only.
@@ -122,8 +140,9 @@ class ProcessManager : public content::NotificationObserver {
   // onSuspendCanceled() event to it.
   void CancelSuspend(const Extension* extension);
 
-  // Ensures background hosts are loaded for a new browser window.
-  void OnBrowserWindowReady();
+  // Creates background hosts if the embedder is ready and they are not already
+  // loaded.
+  void MaybeCreateStartupBackgroundHosts();
 
   // Gets the BrowserContext associated with site_instance_ and all other
   // related SiteInstances.
@@ -144,6 +163,10 @@ class ProcessManager : public content::NotificationObserver {
       content::BrowserContext* original_context,
       ProcessManager* original_manager);
 
+  bool startup_background_hosts_created_for_test() const {
+    return startup_background_hosts_created_;
+  }
+
  protected:
   // If |context| is incognito pass the master context as |original_context|.
   // Otherwise pass the same context for both.
@@ -160,7 +183,7 @@ class ProcessManager : public content::NotificationObserver {
 
   // Load all background pages once the profile data is ready and the pages
   // should be loaded.
-  void CreateBackgroundHostsForProfileStartup();
+  void CreateStartupBackgroundHosts();

[Yoyo Zhou, 2014/07/15 02:13:22]

nit: does this need to be protected? can it be in private?

[James Cook, 2014/07/15 17:02:52]

Good catch! Moved to private.

 
   content::NotificationRegistrar registrar_;
 
@@ -216,9 +239,6 @@ class ProcessManager : public content::NotificationObserver {
   // Clears background page data for this extension.
   void ClearBackgroundPageData(const std::string& extension_id);
 
-  // Returns true if loading background pages should be deferred.
-  bool DeferLoadingBackgroundHosts() const;
-
   void OnDevToolsStateChanged(content::DevToolsAgentHost*, bool attached);
 
   // Contains all active extension-related RenderViewHost instances for all