Implement referrerpolicy attr for iframes

Source/core/html/HTMLIFrameElement.cpp

Index: Source/core/html/HTMLIFrameElement.cpp
diff --git a/Source/core/html/HTMLIFrameElement.cpp b/Source/core/html/HTMLIFrameElement.cpp
index ef5413c522711007db13895f5ceceafad5062fee..38bbfc892ae4ab978a58a2aea49c1853fb3d6073 100644
--- a/Source/core/html/HTMLIFrameElement.cpp
+++ b/Source/core/html/HTMLIFrameElement.cpp
@@ -32,6 +32,7 @@
 #include "core/html/HTMLDocument.h"
 #include "core/inspector/ConsoleMessage.h"
 #include "core/layout/LayoutIFrame.h"
+#include "platform/RuntimeEnabledFeatures.h"
 
 namespace blink {
 
@@ -120,6 +121,10 @@ void HTMLIFrameElement::parseAttribute(const QualifiedName& name, const AtomicSt
     } else if (name == sandboxAttr) {
         m_sandbox->setValue(value);
         UseCounter::count(document(), UseCounter::SandboxViaIFrame);
+    } else if (RuntimeEnabledFeatures::referrerPolicyAttributeEnabled() && name == referrerpolicyAttr) {
+        m_referrerPolicy = ReferrerPolicyDefault;
+        if (!value.isNull())
+            SecurityPolicy::referrerPolicyFromString(value, &m_referrerPolicy);
     } else {
         HTMLFrameElementBase::parseAttribute(name, value);
     }
@@ -173,4 +178,12 @@ void HTMLIFrameElement::valueChanged()
     setSynchronizedLazyAttribute(sandboxAttr, m_sandbox->value());
 }
 
+bool HTMLIFrameElement::referrerPolicyAttribute(ReferrerPolicy* policy)

[Yoav Weiss, 2015/09/08 09:55:08]

Like I wrote at the caller site, it'd be better to just return the policy and
check the runtime flag at the caller.

[estark, 2015/09/08 14:40:34]

Done.

[estark, 2015/09/08 14:40:34]

Done.

+{
+    if (!RuntimeEnabledFeatures::referrerPolicyAttributeEnabled())
+        return false;
+
+    *policy = m_referrerPolicy;
+    return true;
+}
 }