Implement NavigationThrottle::BLOCK_REQUEST_AND_COLLAPSE.

third_party/WebKit/public/web/WebFrame.h

Index: third_party/WebKit/public/web/WebFrame.h
diff --git a/third_party/WebKit/public/web/WebFrame.h b/third_party/WebKit/public/web/WebFrame.h
index 804dfd2fe496960fd5466fc7b85ef2e0dbc5f3ad..ffcbe1e3626e082c33330d7af3efdcfa22f67392 100644
--- a/third_party/WebKit/public/web/WebFrame.h
+++ b/third_party/WebKit/public/web/WebFrame.h
@@ -184,6 +184,11 @@ class WebFrame {
   virtual bool HasHorizontalScrollbar() const = 0;
   virtual bool HasVerticalScrollbar() const = 0;
 
+  // Whether to collapse the frame's owner element in the embedder document,
+  // that is, to remove it from the layout as if it did not exist. Only works
+  // for <iframe> owner elements.
+  BLINK_EXPORT void Collapse(bool);
+
   // Hierarchy ----------------------------------------------------------
 
   // Returns the containing view.