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

chrome/browser/devtools/devtools_window.cc

Index: chrome/browser/devtools/devtools_window.cc
diff --git a/chrome/browser/devtools/devtools_window.cc b/chrome/browser/devtools/devtools_window.cc
index 41863af5b69883153a826134e32132da0dd64d0c..cb69ffda23a8ef888a3119052771f989df543edb 100644
--- a/chrome/browser/devtools/devtools_window.cc
+++ b/chrome/browser/devtools/devtools_window.cc
@@ -47,6 +47,7 @@
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_contents.h"
+#include "content/public/browser/web_contents_source.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/url_constants.h"
 #include "net/base/escape.h"
@@ -773,6 +774,8 @@ DevToolsWindow* DevToolsWindow::Create(
                           can_dock, settings));
   scoped_ptr<WebContents> main_web_contents(
       WebContents::Create(WebContents::CreateParams(profile)));
+  WebContentsSource::CreateForWebContentsAndLocation(main_web_contents.get(),
+                                                     FROM_HERE);
   main_web_contents->GetController().LoadURL(
       DecorateFrontendURL(url), content::Referrer(),
       ui::PAGE_TRANSITION_AUTO_TOPLEVEL, std::string());