Keep browser process alive while there are platform apps with background pages running.

chrome/browser/extensions/extension_host.cc

 // 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.
 
 #include "chrome/browser/extensions/extension_host.h"
 
 #include <list>
 
 #include "base/bind.h"
 #include "base/memory/singleton.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/browser_shutdown.h"
 #include "chrome/browser/extensions/event_router.h"
 #include "chrome/browser/extensions/extension_process_manager.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/extensions/extension_tab_util.h"
 #include "chrome/browser/extensions/window_controller.h"
 #include "chrome/browser/file_select_helper.h"
+#include "chrome/browser/lifetime/application_lifetime.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/app_modal_dialogs/javascript_dialog_creator.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/prefs/prefs_tab_helper.h"
 #include "chrome/browser/ui/tab_contents/tab_contents.h"
 #include "chrome/browser/view_type_utils.h"
 #include "chrome/common/chrome_constants.h"
@@ skipping 23 matching lines @@
 using WebKit::WebDragOperation;
 using WebKit::WebDragOperationsMask;
 using content::NativeWebKeyboardEvent;
 using content::OpenURLParams;
 using content::RenderViewHost;
 using content::SiteInstance;
 using content::WebContents;
 
 namespace extensions {
 
+bool ExtensionHost::Delegate::KeepsBrowserProcessAlive() {
+  // By default hosts do not keep the browser process alive.
+  return false;
+}
+
 // Helper class that rate-limits the creation of renderer processes for
 // ExtensionHosts, to avoid blocking the UI.
 class ExtensionHost::ProcessCreationQueue {
  public:
   static ProcessCreationQueue* GetInstance() {
     return Singleton<ProcessCreationQueue>::get();
   }
 
   // Add a host to the queue for RenderView creation.
   void CreateSoon(ExtensionHost* host) {
@@ skipping 41 matching lines @@
   typedef std::list<ExtensionHost*> Queue;
   Queue queue_;
   bool pending_create_;
   base::WeakPtrFactory<ProcessCreationQueue> ptr_factory_;
 };
 
 ////////////////
 // ExtensionHost
 
 ExtensionHost::ExtensionHost(const Extension* extension,
+                             Delegate* delegate,
                              SiteInstance* site_instance,
                              const GURL& url,
                              chrome::ViewType host_type)
     : extension_(extension),
       extension_id_(extension->id()),
       profile_(Profile::FromBrowserContext(
           site_instance->GetBrowserContext())),
+      delegate_(delegate),
       render_view_host_(NULL),
       did_stop_loading_(false),
       document_element_available_(false),
       initial_url_(url),
       ALLOW_THIS_IN_INITIALIZER_LIST(
           extension_function_dispatcher_(profile_, this)),
       extension_host_type_(host_type),
       associated_web_contents_(NULL) {
   host_contents_.reset(WebContents::Create(
       profile_, site_instance, MSG_ROUTING_NONE, NULL));
   content::WebContentsObserver::Observe(host_contents_.get());
   host_contents_->SetDelegate(this);
   chrome::SetViewType(host_contents_.get(), host_type);
 
   PrefsTabHelper::CreateForWebContents(host_contents());
 
   render_view_host_ = host_contents_->GetRenderViewHost();
 
   // Listen for when an extension is unloaded from the same profile, as it may
   // be the same extension that this points to.
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_UNLOADED,
                  content::Source<Profile>(profile_));
+
+  if (delegate_->KeepsBrowserProcessAlive())
+    browser::StartKeepAlive();
 }
 
 ExtensionHost::~ExtensionHost() {
   if (extension_host_type_ == chrome::VIEW_TYPE_EXTENSION_BACKGROUND_PAGE &&
       extension_ && extension_->has_lazy_background_page()) {
     UMA_HISTOGRAM_LONG_TIMES("Extensions.EventPageActiveTime",
                              since_created_.Elapsed());
   }
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_EXTENSION_HOST_DESTROYED,
       content::Source<Profile>(profile_),
       content::Details<ExtensionHost>(this));
   ProcessCreationQueue::GetInstance()->Remove(this);
+
+  if (delegate_->KeepsBrowserProcessAlive())
+    browser::EndKeepAlive();
 }
 
 void ExtensionHost::CreateView(Browser* browser) {
 #if defined(TOOLKIT_VIEWS)
   view_.reset(new ExtensionViewViews(this, browser));
   // We own |view_|, so don't auto delete when it's removed from the view
   // hierarchy.
   view_->set_owned_by_client();
 #elif defined(OS_MACOSX)
   view_.reset(new ExtensionViewMac(this, browser));
@@ skipping 454 matching lines @@
 }
 
 void ExtensionHost::RenderViewReady() {
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_EXTENSION_HOST_CREATED,
       content::Source<Profile>(profile_),
       content::Details<ExtensionHost>(this));
 }
 
 }  // namespace extensions