Expose GetLastCommitedOrigin() on WebContents and use it in about:blank

content/public/browser/web_contents.h

Index: content/public/browser/web_contents.h
diff --git a/content/public/browser/web_contents.h b/content/public/browser/web_contents.h
index a0ea79fb0128b5e72d8f62f549b2761217f7655d..b9cb4dff319eea446dd17ec8444f4da6d31a5c8a 100644
--- a/content/public/browser/web_contents.h
+++ b/content/public/browser/web_contents.h
@@ -25,6 +25,7 @@
 #include "ui/base/window_open_disposition.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/native_widget_types.h"
+#include "url/origin.h"
 
 #if defined(OS_ANDROID)
 #include "base/android/scoped_java_ref.h"
@@ -202,6 +203,9 @@ class WebContents : public PageNavigator,
   // context.
   virtual const GURL& GetLastCommittedURL() const = 0;
 
+  // Gets the last committed origin of the main frame of WebContents.
+  virtual const url::Origin& GetLastCommittedOrigin() const = 0;
+
   // Return the currently active RenderProcessHost and RenderViewHost. Each of
   // these may change over time.
   virtual RenderProcessHost* GetRenderProcessHost() const = 0;