Make Foreign Fetch an origin trial.

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 3b4bd7d1227acbcbbf72e3128ecd72618fc78aac..53e4cfc88df21d283fbc6c836bcc8dfae7362616 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 "core/origin_trials/OriginTrials.h"
 #include "platform/RuntimeEnabledFeatures.h"
 #include "wtf/HashMap.h"
 
@@ -54,8 +55,6 @@ 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;
@@ -63,7 +62,9 @@ static RelList::SupportedTokens& supportedTokens()
 
 bool RelList::validateTokenValue(const AtomicString& tokenValue, ExceptionState&) const
 {
-    return supportedTokens().contains(tokenValue);
+    if (supportedTokens().contains(tokenValue))
+        return true;
+    return OriginTrials::linkServiceWorkerEnabled(m_element->getExecutionContext()) && tokenValue == "serviceworker";
 }
 
 DEFINE_TRACE(RelList)