Implement support for link type serviceworker in link elements.

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

Index: third_party/WebKit/Source/core/html/RelList.cpp
diff --git a/third_party/WebKit/Source/core/html/RelList.cpp b/third_party/WebKit/Source/core/html/RelList.cpp
index 18a2ecdaa776a3c636d9ee66aa3fcd28dbe8145e..42b7e99b5b65d6fb7b8ea4813cce10c2dd2d5a62 100644
--- a/third_party/WebKit/Source/core/html/RelList.cpp
+++ b/third_party/WebKit/Source/core/html/RelList.cpp
@@ -5,6 +5,7 @@
 #include "core/html/RelList.h"
 
 #include "core/dom/Document.h"
+#include "platform/RuntimeEnabledFeatures.h"
 #include "wtf/HashMap.h"
 
 namespace blink {
@@ -67,6 +68,8 @@ static RelList::SupportedTokens& supportedTokens()
         supportedValuesMap.add("manifest");
         supportedValuesMap.add("apple-touch-icon");
         supportedValuesMap.add("apple-touch-icon-precomposed");
+        if (RuntimeEnabledFeatures::linkServiceworkerEnabled())
+            supportedValuesMap.add("serviceworker");
     }
 
     return supportedValuesMap;