Implement NavigationThrottle::BLOCK_REQUEST_AND_COLLAPSE.

third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.h

Index: third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.h
diff --git a/third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.h b/third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.h
index 9cb154427fb56f397c53e0d0076b7d07cff818c5..57d3a7bb1f5a4c5259d145984f0ae9187854825c 100644
--- a/third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.h
+++ b/third_party/WebKit/Source/core/html/HTMLFrameOwnerElement.h
@@ -56,6 +56,10 @@ class CORE_EXPORT HTMLFrameOwnerElement : public HTMLElement,
   // return any LayoutObject when using fallback content.
   LayoutPart* GetLayoutPart() const;
 
+  // Whether to collapse the frame owner element in the embedder document. That
+  // is, to remove it from the layout as if it did not exist.
+  virtual void SetCollapsed(bool) {}
+
   Document* getSVGDocument(ExceptionState&) const;
 
   virtual bool LoadedNonEmptyDocument() const { return false; }