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

components/constrained_window/constrained_window_views.cc

Index: components/constrained_window/constrained_window_views.cc
diff --git a/components/constrained_window/constrained_window_views.cc b/components/constrained_window/constrained_window_views.cc
index 5ae6cd7776da6ae7eb24433ddda5d07c808fa9bd..d3c2a5dd0874c3024e999238cf21c92360895975 100644
--- a/components/constrained_window/constrained_window_views.cc
+++ b/components/constrained_window/constrained_window_views.cc
@@ -11,6 +11,7 @@
 #include "components/web_modal/web_contents_modal_dialog_host.h"
 #include "components/web_modal/web_contents_modal_dialog_manager.h"
 #include "components/web_modal/web_contents_modal_dialog_manager_delegate.h"
+#include "content/public/browser/web_contents_source.h"
 #include "ui/views/border.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_observer.h"
@@ -146,6 +147,16 @@ views::Widget* ShowWebModalDialogViews(
 
 views::Widget* CreateWebModalDialogViews(views::WidgetDelegate* dialog,
                                          content::WebContents* web_contents) {
+  // Code to help trace the source of http://crbug.com/538612
+  WebContentsSource* web_contents_creation_site =
+      WebContentsSource::FromWebContents(web_contents);
+  tracked_objects::Location created_location;
+  if (web_contents_creation_site)
+    created_location = web_contents_creation_site->created_location();
+  base::debug::Alias(&created_location);

[Mike Wittman, 2015/11/11 17:15:28]

needs an #include

[hcarmona, 2015/11/11 19:57:58]

Done.

+  CHECK(
+      web_modal::WebContentsModalDialogManager::FromWebContents(web_contents));
+
   DCHECK_EQ(ui::MODAL_TYPE_CHILD, dialog->GetModalType());
   return views::DialogDelegate::CreateDialogWidget(
       dialog, nullptr,