Make sure WebContents passed to chrome_page_zoom::Zoom() have a ZoomController.

chrome/browser/ui/panels/panel_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/ui/panels/panel_host.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/chrome_page_zoom.h"
 #include "chrome/browser/extensions/chrome_extension_web_contents_observer.h"
 #include "chrome/browser/extensions/window_controller.h"
 #include "chrome/browser/favicon/favicon_tab_helper.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sessions/session_tab_helper.h"
 #include "chrome/browser/ui/browser_navigator.h"
 #include "chrome/browser/ui/panels/panel.h"
 #include "chrome/browser/ui/prefs/prefs_tab_helper.h"
+#include "chrome/browser/ui/zoom/zoom_controller.h"
 #include "content/public/browser/invalidate_type.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/notification_types.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_contents.h"
 #include "extensions/browser/view_type_utils.h"
@@ skipping 17 matching lines @@
 
 void PanelHost::Init(const GURL& url) {
   if (url.is_empty())
     return;
 
   content::WebContents::CreateParams create_params(
       profile_, content::SiteInstance::CreateForURL(profile_, url));
   web_contents_.reset(content::WebContents::Create(create_params));
   extensions::SetViewType(web_contents_.get(), extensions::VIEW_TYPE_PANEL);
   web_contents_->SetDelegate(this);
+  // web_contents_ may be passed to chrome_page_zoom::Zoom(), so it needs
+  // a ZoomController.
+  ZoomController::CreateForWebContents(web_contents_.get());
   content::WebContentsObserver::Observe(web_contents_.get());
 
   // Needed to give the web contents a Tab ID. Extension APIs
   // expect web contents to have a Tab ID.
   SessionTabHelper::CreateForWebContents(web_contents_.get());
   SessionTabHelper::FromWebContents(web_contents_.get())->SetWindowID(
       panel_->session_id());
 
   FaviconTabHelper::CreateForWebContents(web_contents_.get());
   PrefsTabHelper::CreateForWebContents(web_contents_.get());
@@ skipping 193 matching lines @@
 }
 
 void PanelHost::StopLoading() {
   content::RecordAction(UserMetricsAction("Stop"));
   web_contents_->Stop();
 }
 
 void PanelHost::Zoom(content::PageZoom zoom) {
   chrome_page_zoom::Zoom(web_contents_.get(), zoom);
 }