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

ui/views/controls/webview/webview.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 "ui/views/controls/webview/webview.h"
 
 #include "content/public/browser/browser_accessibility_state.h"
 #include "content/public/browser/browser_context.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_source.h"
 #include "ipc/ipc_message.h"
 #include "ui/accessibility/ax_enums.h"
 #include "ui/accessibility/ax_view_state.h"
 #include "ui/events/event.h"
 #include "ui/views/controls/native/native_view_host.h"
 #include "ui/views/focus/focus_manager.h"
 #include "ui/views/views_delegate.h"
 
 namespace views {
 
@@ skipping 359 matching lines @@
       content::BrowserContext* browser_context) {
   content::WebContents* contents = NULL;
   if (ViewsDelegate::GetInstance()) {
     contents =
         ViewsDelegate::GetInstance()->CreateWebContents(browser_context, NULL);
   }
 
   if (!contents) {
     content::WebContents::CreateParams create_params(
         browser_context, NULL);
-    return content::WebContents::Create(create_params);
+    content::WebContents* web_contents =
+        content::WebContents::Create(create_params);
+    WebContentsSource::CreateForWebContentsAndLocation(web_contents, FROM_HERE);
+    return web_contents;
   }
 
   return contents;
 }
 
 }  // namespace views