Track where WebContents are created in order to better understand issue.

apps/custom_launcher_page_contents.cc

 // Copyright 2014 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 "apps/custom_launcher_page_contents.h"
 
 #include <string>
 
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/extensions/chrome_extension_web_contents_observer.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_source.h"
 #include "content/public/common/renderer_preferences.h"
 #include "extensions/browser/app_window/app_delegate.h"
 #include "extensions/browser/app_window/app_web_contents_helper.h"
 #include "extensions/browser/view_type_utils.h"
 #include "extensions/common/extension_messages.h"
 
 namespace apps {
 
 CustomLauncherPageContents::CustomLauncherPageContents(
     scoped_ptr<extensions::AppDelegate> app_delegate,
     const std::string& extension_id)
     : app_delegate_(app_delegate.Pass()), extension_id_(extension_id) {
 }
 
 CustomLauncherPageContents::~CustomLauncherPageContents() {
 }
 
 void CustomLauncherPageContents::Initialize(content::BrowserContext* context,
                                             const GURL& url) {
   web_contents_.reset(
       content::WebContents::Create(content::WebContents::CreateParams(
           context, content::SiteInstance::CreateForURL(context, url))));
 
+  WebContentsSource::CreateForWebContentsAndLocation(web_contents_.get(),
+                                                     FROM_HERE);
   web_contents_->GetMutableRendererPrefs()
       ->browser_handles_all_top_level_requests = true;
   web_contents_->GetRenderViewHost()->SyncRendererPrefs();
 
   helper_.reset(new extensions::AppWebContentsHelper(
       context, extension_id_, web_contents_.get(), app_delegate_.get()));
   web_contents_->SetDelegate(this);
 
   extensions::SetViewType(web_contents(), extensions::VIEW_TYPE_LAUNCHER_PAGE);
 
@@ skipping 78 matching lines @@
 
 bool CustomLauncherPageContents::CheckMediaAccessPermission(
     content::WebContents* web_contents,
     const GURL& security_origin,
     content::MediaStreamType type) {
   DCHECK_EQ(web_contents_.get(), web_contents);
   return helper_->CheckMediaAccessPermission(security_origin, type);
 }
 
 }  // namespace apps