Lazy creating of background pages --enable-lazy-background-pages)

chrome/browser/ui/gtk/browser_actions_toolbar_gtk.cc

Index: chrome/browser/ui/gtk/browser_actions_toolbar_gtk.cc
diff --git a/chrome/browser/ui/gtk/browser_actions_toolbar_gtk.cc b/chrome/browser/ui/gtk/browser_actions_toolbar_gtk.cc
index 5611b0cee7e841f02e5531e04b904c7bd1393bba..cc01309dc3aee8bac76c5e64b859794113853916 100644
--- a/chrome/browser/ui/gtk/browser_actions_toolbar_gtk.cc
+++ b/chrome/browser/ui/gtk/browser_actions_toolbar_gtk.cc
@@ -7,6 +7,7 @@
 #include <algorithm>
 #include <vector>
 
+#include "base/command_line.h"
 #include "base/i18n/rtl.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/extensions/extension_browser_event_router.h"
@@ -27,6 +28,7 @@
 #include "chrome/browser/ui/gtk/view_id_util.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
 #include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_action.h"
 #include "chrome/common/extensions/extension_resource.h"
@@ -94,7 +96,8 @@ class BrowserActionButton : public NotificationObserver,
         image_(NULL),
         tracker_(this),
         tab_specific_icon_(NULL),
-        default_icon_(NULL) {
+        default_icon_(NULL),
+        waiting_for_background_page_(false) {
     button_.reset(new CustomDrawButton(
         theme_provider,
         IDR_BROWSER_ACTION,
@@ -153,10 +156,17 @@ class BrowserActionButton : public NotificationObserver,
   void Observe(int type,
                const NotificationSource& source,
                const NotificationDetails& details) {
-    if (type == chrome::NOTIFICATION_EXTENSION_BROWSER_ACTION_UPDATED)
+    if (type == chrome::NOTIFICATION_EXTENSION_BROWSER_ACTION_UPDATED) {
       UpdateState();
-    else
+    } else if (type == chrome::NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING) {
+      BrowserActionExecuted();
+      registrar_.Remove(this,
+                        chrome::NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING,
+                        Source<Profile>(toolbar_->browser()->profile()));
+      waiting_for_background_page_ = false;
+    } else {
       NOTREACHED();
+    }
   }
 
   // ImageLoadingTracker::Observer implementation.
@@ -169,6 +179,34 @@ class BrowserActionButton : public NotificationObserver,
     UpdateState();
   }
 
+  bool IsBackgroundPageMissing() {
+    if (extension_->background_url().is_valid()) {
+      ExtensionProcessManager* pm =
+          toolbar_->browser()->profile()->GetExtensionProcessManager();
+      return pm->GetBackgroundHostForExtension(extension_) == NULL;
+    }
+
+    return false;  // Extension doesn't have a background page.
+  }
+
+
+  void AddObserverForBackgroundPageLoaded() {
+    if (waiting_for_background_page_)
+      return;  // NotificationRegistrar doesn't like dups.
+    registrar_.Add(this,
+                   chrome::NOTIFICATION_EXTENSION_HOST_DID_STOP_LOADING,
+                   Source<Profile>(toolbar_->browser()->profile()));
+    waiting_for_background_page_ = true;
+  }
+
+  void BrowserActionExecuted() {
+    ExtensionService* service =
+        toolbar_->browser()->profile()->GetExtensionService();
+    service->browser_event_router()->BrowserActionExecuted(
+        toolbar_->browser()->profile(), extension_->id(),
+        toolbar_->browser());
+  }
+
   // Updates the button based on the latest state from the associated
   // browser action.
   void UpdateState() {
@@ -289,11 +327,20 @@ class BrowserActionButton : public NotificationObserver,
     if (action->ShowPopup(false))
       return;
 
-    ExtensionService* service =
-        action->toolbar_->browser()->profile()->GetExtensionService();
-    service->browser_event_router()->BrowserActionExecuted(
-        action->toolbar_->browser()->profile(), action->extension_->id(),
-        action->toolbar_->browser());
+    // Time to create the background page!
+    if (CommandLine::ForCurrentProcess()->HasSwitch(
+            switches::kEnableLazyBackgroundPages) &&
+        action->IsBackgroundPageMissing()) {
+      // Dispatch the OnClicked event when the background page is loaded.
+      action->AddObserverForBackgroundPageLoaded();
+
+      ExtensionProcessManager* pm =
+          action->toolbar_->browser()->profile()->GetExtensionProcessManager();
+      pm->CreateBackgroundHost(action->extension_,
+                               action->extension_->background_url());
+    } else {
+      action->BrowserActionExecuted();
+    }
   }
 
   static gboolean OnExposeEvent(GtkWidget* widget,
@@ -359,6 +406,8 @@ class BrowserActionButton : public NotificationObserver,
   scoped_ptr<MenuGtk> context_menu_;
   scoped_refptr<ExtensionContextMenuModel> context_menu_model_;
 
+  bool waiting_for_background_page_;
+
   friend class BrowserActionsToolbarGtk;
 };