Remove support for the obsolete <isindex> tag.

Source/core/html/FormDataList.cpp

 /*
  * Copyright (C) 2005, 2006, 2008 Apple 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 112 matching lines @@
                     if (!file->fileSystemURL().isEmpty())
                         formData->appendFileSystemURL(file->fileSystemURL());
                 } else {
                     formData->appendBlob(value.blob()->uuid(), value.blob()->blobDataHandle());
                 }
             } else {
                 formData->appendData(value.data().data(), value.data().length());
             }
             formData->appendData("\r\n", 2);
         } else {
-            // Omit the name "isindex" if it's the first form data element.
-            // FIXME: Why is this a good rule? Is this obsolete now?
-            if (encodedData.isEmpty() && key.data() == "isindex")
-                FormDataBuilder::encodeStringAsFormData(encodedData, value.data());
-            else
-                FormDataBuilder::addKeyValuePairAsFormData(encodedData, key.data(), value.data(), encodingType);
+            FormDataBuilder::addKeyValuePairAsFormData(encodedData, key.data(), value.data(), encodingType);
         }
     }
 
     if (isMultiPartForm)
         FormDataBuilder::addBoundaryToMultiPartHeader(encodedData, formData->boundary().data(), true);
 
     formData->appendData(encodedData.data(), encodedData.size());
 }
 
 } // namespace