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

chrome/browser/memory/tab_manager.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/memory/tab_manager.h"
 
 #include <algorithm>
 #include <set>
 #include <vector>
 
@@ skipping 24 matching lines @@
 #include "chrome/browser/ui/tab_contents/tab_contents_iterator.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/browser/ui/tabs/tab_utils.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/url_constants.h"
 #include "components/metrics/system_memory_stats_recorder.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_source.h"
 #include "content/public/common/page_importance_signals.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/memory/tab_manager_delegate_chromeos.h"
 #endif
 
 using base::TimeDelta;
 using base::TimeTicks;
 using content::BrowserThread;
 using content::WebContents;
@@ skipping 422 matching lines @@
   // Can't discard tabs that are already discarded.
   if (GetWebContentsData(old_contents)->IsDiscarded())
     return nullptr;
 
   // Record statistics before discarding to capture the memory state that leads
   // to the discard.
   RecordDiscardStatistics();
 
   WebContents* null_contents =
       WebContents::Create(WebContents::CreateParams(model->profile()));
+  WebContentsSource::CreateForWebContentsAndLocation(null_contents, FROM_HERE);
   // Copy over the state from the navigation controller to preserve the
   // back/forward history and to continue to display the correct title/favicon.
   null_contents->GetController().CopyStateFrom(old_contents->GetController());
 
   // Make sure to persist the last active time property.
   null_contents->SetLastActiveTime(old_contents->GetLastActiveTime());
   // Copy over the discard count.
   WebContentsData::CopyState(old_contents, null_contents);
 
   // Replace the discarded tab with the null version.
@@ skipping 75 matching lines @@
   // sudden_termination_allowed false, and that covers too many common pages
   // with ad networks and statistics scripts.  Ideally check for beforeUnload
   // handlers, which are likely to present a dialog asking if the user wants to
   // discard state.  crbug.com/123049.
 
   // Being more recently active is more important.
   return first.last_active > second.last_active;
 }
 
 }  // namespace memory