Implement support for link type serviceworker in link elements.

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Rob Buis (rwlbuis@gmail.com)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 175 matching lines @@
         m_type = value;
         process();
     } else if (name == asAttr) {
         m_as = value;
         process();
     } else if (name == sizesAttr) {
         m_sizes->setValue(value);
     } else if (name == mediaAttr) {
         m_media = value.lower();
         process();
+    } else if (name == scopeAttr) {
+        m_scope = value;
+        process();
     } else if (name == disabledAttr) {
         UseCounter::count(document(), UseCounter::HTMLLinkElementDisabled);
         if (LinkStyle* link = linkStyle())
             link->setDisabledState(!value.isNull());
     } else {
         if (name == titleAttr) {
             if (LinkStyle* link = linkStyle())
                 link->setSheetTitle(value);
         }
 
@@ skipping 17 matching lines @@
     if (!visible) {
         ASSERT(!linkStyle() || !linkStyle()->hasSheet());
         return nullptr;
     }
 
     if (!m_link) {
         if (m_relAttribute.isImport()) {
             m_link = LinkImport::create(this);
         } else if (m_relAttribute.isManifest()) {
             m_link = LinkManifest::create(this);
+        } else if (RuntimeEnabledFeatures::linkServiceWorkerEnabled() && m_relAttribute.isServiceWorker()) {
+            if (document().frame())
+                m_link = document().frame()->loader().client()->createServiceWorkerLinkResource(this);
         } else {
             OwnPtrWillBeRawPtr<LinkStyle> link = LinkStyle::create(this);
             if (fastHasAttribute(disabledAttr)) {
                 UseCounter::count(document(), UseCounter::HTMLLinkElementDisabled);
                 link->setDisabledState(true);
             }
             m_link = link.release();
         }
     }
 
@@ skipping 544 matching lines @@
 }
 
 DEFINE_TRACE(LinkStyle)
 {
     visitor->trace(m_sheet);
     LinkResource::trace(visitor);
     ResourceOwner<StyleSheetResource>::trace(visitor);
 }
 
 } // namespace blink