Implement NavigationThrottle::BLOCK_REQUEST_AND_COLLAPSE.

third_party/WebKit/Source/core/html/HTMLIFrameElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLIFrameElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLIFrameElement.cpp b/third_party/WebKit/Source/core/html/HTMLIFrameElement.cpp
index c58604cddcba2c973a70bf50e5b9cffcf2e86fa8..37be21f2a01c77749140944d1ea3d61e9c345c2a 100644
--- a/third_party/WebKit/Source/core/html/HTMLIFrameElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLIFrameElement.cpp
@@ -39,6 +39,7 @@ using namespace HTMLNames;
 inline HTMLIFrameElement::HTMLIFrameElement(Document& document)
     : HTMLFrameElementBase(iframeTag, document),
       did_load_non_empty_document_(false),
+      collapsed_by_client_(false),
       sandbox_(HTMLIFrameElementSandbox::Create(this)),
       allow_(HTMLIFrameElementAllow::Create(this)),
       referrer_policy_(kReferrerPolicyDefault) {}
@@ -54,6 +55,18 @@ DEFINE_TRACE(HTMLIFrameElement) {
 
 HTMLIFrameElement::~HTMLIFrameElement() {}
 
+void HTMLIFrameElement::SetCollapsed(bool collapse) {
+  if (collapsed_by_client_ == collapse)
+    return;
+
+  collapsed_by_client_ = collapse;
+
+  // This is always called in response to an IPC, so should not happen in the
+  // middle of a style recalc.
+  DCHECK(!GetDocument().InStyleRecalc());
+  LazyReattachIfAttached();
+}
+
 DOMTokenList* HTMLIFrameElement::sandbox() const {
   return sandbox_.Get();
 }
@@ -168,7 +181,8 @@ void HTMLIFrameElement::ParseAttribute(
 }
 
 bool HTMLIFrameElement::LayoutObjectIsNeeded(const ComputedStyle& style) {
-  return ContentFrame() && HTMLElement::LayoutObjectIsNeeded(style);
+  return ContentFrame() && !collapsed_by_client_ &&
+         HTMLElement::LayoutObjectIsNeeded(style);
 }
 
 LayoutObject* HTMLIFrameElement::CreateLayoutObject(const ComputedStyle&) {