Propagate inert state to OOPIFs when a modal dialog is active

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

Index: third_party/WebKit/Source/core/html/HTMLElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLElement.cpp b/third_party/WebKit/Source/core/html/HTMLElement.cpp
index cdcb4598f15308ca57a04041dc9fd536be469c75..8a21008035ec33e5f7c58db92dc54341b9ad0fc1 100644
--- a/third_party/WebKit/Source/core/html/HTMLElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLElement.cpp
@@ -56,6 +56,7 @@
 #include "core/html/HTMLBRElement.h"
 #include "core/html/HTMLDimension.h"
 #include "core/html/HTMLFormElement.h"
+#include "core/html/HTMLFrameOwnerElement.h"
 #include "core/html/HTMLInputElement.h"
 #include "core/html/HTMLTemplateElement.h"
 #include "core/html/parser/HTMLParserIdioms.h"
@@ -466,6 +467,9 @@ void HTMLElement::ParseAttribute(const AttributeModificationParams& params) {
     PseudoStateChanged(CSSSelector::kPseudoLang);
   } else if (params.name == inertAttr) {
     UseCounter::Count(GetDocument(), WebFeature::kInertAttribute);
+    UpdateDistribution();
+    GetDocument().GetFrame()->SetIsInert(GetDocument().LocalOwner() &&
+                                         GetDocument().LocalOwner()->IsInert());
   } else if (params.name == nonceAttr) {
     if (params.new_value != g_empty_atom)
       setNonce(params.new_value);