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

chrome/browser/extensions/extension_host.cc

Index: chrome/browser/extensions/extension_host.cc
diff --git a/chrome/browser/extensions/extension_host.cc b/chrome/browser/extensions/extension_host.cc
index d370c268c555b51ae652538ac323cac0c26de36b..943ad18fef68d82bb22634cd2e5e96058a6681b2 100644
--- a/chrome/browser/extensions/extension_host.cc
+++ b/chrome/browser/extensions/extension_host.cc
@@ -21,6 +21,7 @@
 #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"
@@ -64,6 +65,11 @@ 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 {
@@ -125,6 +131,7 @@ class ExtensionHost::ProcessCreationQueue {
 // ExtensionHost
 
 ExtensionHost::ExtensionHost(const Extension* extension,
+                             Delegate* delegate,
                              SiteInstance* site_instance,
                              const GURL& url,
                              chrome::ViewType host_type)
@@ -132,6 +139,7 @@ ExtensionHost::ExtensionHost(const 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),
@@ -154,6 +162,9 @@ ExtensionHost::ExtensionHost(const Extension* extension,
   // 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() {
@@ -167,6 +178,9 @@ ExtensionHost::~ExtensionHost() {
       content::Source<Profile>(profile_),
       content::Details<ExtensionHost>(this));
   ProcessCreationQueue::GetInstance()->Remove(this);
+
+  if (delegate_->KeepsBrowserProcessAlive())
+    browser::EndKeepAlive();
 }
 
 void ExtensionHost::CreateView(Browser* browser) {