Remove iframe@seamless

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 016fba4ec0ed6511a7800d0ad684908458b95b1c..c53dc02d3f76c50fe628fea5f6ce500f7e0decee 100644
--- a/Source/core/html/HTMLIFrameElement.cpp
+++ b/Source/core/html/HTMLIFrameElement.cpp
@@ -49,7 +49,7 @@ PassRefPtr<HTMLIFrameElement> HTMLIFrameElement::create(Document& document)
 
 bool HTMLIFrameElement::isPresentationAttribute(const QualifiedName& name) const
 {
-    if (name == widthAttr || name == heightAttr || name == alignAttr || name == frameborderAttr || name == seamlessAttr)
+    if (name == widthAttr || name == heightAttr || name == alignAttr || name == frameborderAttr)
         return true;
     return HTMLFrameElementBase::isPresentationAttribute(name);
 }
@@ -87,12 +87,9 @@ void HTMLIFrameElement::parseAttribute(const QualifiedName& name, const AtomicSt
         setSandboxFlags(value.isNull() ? SandboxNone : parseSandboxPolicy(value, invalidTokens));
         if (!invalidTokens.isNull())
             document().addConsoleMessage(OtherMessageSource, ErrorMessageLevel, "Error while parsing the 'sandbox' attribute: " + invalidTokens);
-    } else if (name == seamlessAttr) {
-        // If we're adding or removing the seamless attribute, we need to force the content document to recalculate its StyleResolver.
-        if (contentDocument())
-            contentDocument()->styleResolverChanged(RecalcStyleDeferred);
-    } else
+    } else {
         HTMLFrameElementBase::parseAttribute(name, value);
+    }
 }
 
 bool HTMLIFrameElement::rendererIsNeeded(const RenderStyle& style)
@@ -120,18 +117,9 @@ void HTMLIFrameElement::removedFrom(ContainerNode* insertionPoint)
         toHTMLDocument(document()).removeExtraNamedItem(m_name);
 }
 
-bool HTMLIFrameElement::shouldDisplaySeamlessly() const
-{
-    return contentDocument() && contentDocument()->shouldDisplaySeamlesslyWithParent();
-}
-
 void HTMLIFrameElement::didRecalcStyle(StyleRecalcChange styleChange)
 {
-    if (!shouldDisplaySeamlessly())
-        return;
-    Document* childDocument = contentDocument();
-    if (shouldRecalcStyle(styleChange, childDocument))
-        contentDocument()->recalcStyle(styleChange);
+    // FIXME: Can we remove this function?
 }
 
 bool HTMLIFrameElement::isInteractiveContent() const