Prototype an 'allow-unsandboxed-auxiliary' sandbox flag.

Source/core/dom/SandboxFlags.cpp

 /*
  * Copyright (C) 2013 Google Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 10 matching lines @@
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  */
 
 #include "config.h"
 #include "core/dom/SandboxFlags.h"
 
 #include "core/html/parser/HTMLParserIdioms.h"
+#include "platform/RuntimeEnabledFeatures.h"
 #include "wtf/text/StringBuilder.h"
 
 namespace blink {
 
 SandboxFlags parseSandboxPolicy(const String& policy, String& invalidTokensErrorMessage)
 {
     SpaceSplitString policyTokens(AtomicString(policy), SpaceSplitString::ShouldNotFoldCase);
     return parseSandboxPolicy(policyTokens, invalidTokensErrorMessage);
 }
 
@@ skipping 17 matching lines @@
             flags &= ~SandboxScripts;
             flags &= ~SandboxAutomaticFeatures;
         } else if (equalIgnoringCase(sandboxToken, "allow-top-navigation")) {
             flags &= ~SandboxTopNavigation;
         } else if (equalIgnoringCase(sandboxToken, "allow-popups")) {
             flags &= ~SandboxPopups;
         } else if (equalIgnoringCase(sandboxToken, "allow-pointer-lock")) {
             flags &= ~SandboxPointerLock;
         } else if (equalIgnoringCase(sandboxToken, "allow-orientation-lock")) {
             flags &= ~SandboxOrientationLock;
+        } else if (equalIgnoringCase(sandboxToken, "allow-unsandboxed-auxiliary") && RuntimeEnabledFeatures::unsandboxedAuxiliaryEnabled()) {
+            flags &= ~SandboxPropagatesToAuxiliaryBrowsingContexts;
         } else {
             if (numberOfTokenErrors)
                 tokenErrors.appendLiteral(", '");
             else
                 tokenErrors.append('\'');
             tokenErrors.append(sandboxToken);
             tokenErrors.append('\'');
             numberOfTokenErrors++;
         }
     }
 
     if (numberOfTokenErrors) {
         if (numberOfTokenErrors > 1)
             tokenErrors.appendLiteral(" are invalid sandbox flags.");
         else
             tokenErrors.appendLiteral(" is an invalid sandbox flag.");
         invalidTokensErrorMessage = tokenErrors.toString();
     }
 
     return flags;
 }
 
 }