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

content/browser/web_contents/web_contents_impl.h

 // 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.
 
 #ifndef CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 #define CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_
 
 #include <map>
 #include <set>
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/containers/scoped_ptr_hash_map.h"
+#include "base/debug/stack_trace.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
 #include "base/process/process.h"
 #include "base/values.h"
 #include "content/browser/frame_host/frame_tree.h"
 #include "content/browser/frame_host/navigation_controller_delegate.h"
 #include "content/browser/frame_host/navigation_controller_impl.h"
 #include "content/browser/frame_host/navigator_delegate.h"
 #include "content/browser/frame_host/render_frame_host_delegate.h"
@@ skipping 342 matching lines @@
   void Find(int request_id,
             const base::string16& search_text,
             const blink::WebFindOptions& options) override;
   void StopFinding(StopFindAction action) override;
   void InsertCSS(const std::string& css) override;
   bool WasRecentlyAudible() override;
   void GetManifest(const GetManifestCallback& callback) override;
   void HasManifest(const HasManifestCallback& callback) override;
   void ExitFullscreen() override;
   void ResumeLoadingCreatedWebContents() override;
+  base::debug::StackTrace stack_trace() override;
 #if defined(OS_ANDROID)
   void OnMediaSessionStateChanged();
   void ResumeMediaSession() override;
   void SuspendMediaSession() override;
   void StopMediaSession() override;
 #if !defined(USE_AURA)
   base::android::ScopedJavaLocalRef<jobject> GetJavaWebContents() override;
   virtual WebContentsAndroid* GetWebContentsAndroid();
 #endif  // !USE_AURA
 #elif defined(OS_MACOSX)
@@ skipping 936 matching lines @@
   // Manages all the media player and CDM managers and forwards IPCs to them.
   scoped_ptr<MediaWebContentsObserver> media_web_contents_observer_;
 #endif
 
   scoped_ptr<RenderWidgetHostInputEventRouter> rwh_input_event_router_;
 
   PageImportanceSignals page_importance_signals_;
 
   bool page_scale_factor_is_one_;
 
+  // Temporary to track down http://crbug.com/538612
+  base::debug::StackTrace stack_trace_;
+
   base::WeakPtrFactory<WebContentsImpl> loading_weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsImpl);
 };
 
 // Dangerous methods which should never be made part of the public API, so we
 // grant their use only to an explicit friend list (c++ attorney/client idiom).
 class CONTENT_EXPORT WebContentsImpl::FriendZone {
  private:
   friend class TestNavigationObserver;
   friend class WebContentsAddedObserver;
   friend class ContentBrowserSanityChecker;
 
   FriendZone();  // Not instantiable.
 
   // Adds/removes a callback called on creation of each new WebContents.
   static void AddCreatedCallbackForTesting(const CreatedCallback& callback);
   static void RemoveCreatedCallbackForTesting(const CreatedCallback& callback);
 
   DISALLOW_COPY_AND_ASSIGN(FriendZone);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_WEB_CONTENTS_WEB_CONTENTS_IMPL_H_