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

chrome/browser/ui/app_list/start_page_service.cc

Index: chrome/browser/ui/app_list/start_page_service.cc
diff --git a/chrome/browser/ui/app_list/start_page_service.cc b/chrome/browser/ui/app_list/start_page_service.cc
index c078e7315bfd4dd766594f5a7a75bbdf5a30112a..c2c2e795e8780cd18b620df2be5a5a46822997ae 100644
--- a/chrome/browser/ui/app_list/start_page_service.cc
+++ b/chrome/browser/ui/app_list/start_page_service.cc
@@ -47,6 +47,7 @@
 #include "content/public/browser/speech_recognition_session_preamble.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
+#include "content/public/browser/web_contents_source.h"
 #include "content/public/common/content_switches.h"
 #include "extensions/browser/extension_system_provider.h"
 #include "extensions/browser/extensions_browser_client.h"
@@ -611,6 +612,8 @@ void StartPageService::WebUILoaded() {
 void StartPageService::LoadContents() {
   contents_.reset(content::WebContents::Create(
       content::WebContents::CreateParams(profile_)));
+  WebContentsSource::CreateForWebContentsAndLocation(contents_.get(),
+                                                     FROM_HERE);
   contents_delegate_.reset(new StartPageWebContentsDelegate(profile_));
   contents_->SetDelegate(contents_delegate_.get());