override the new toolkit's contents.rdf for classic/global with our own.

mail/base/jar.mn

@@ -16,6 +16,7 @@ classic.jar:
 +   skin/classic/global/tree/twisty-open.gif        (skin/icons/twisty-open.gif)
 +   skin/classic/global/tree/twisty-clsd.gif        (skin/icons/twisty-clsd.gif)
 +   skin/classic/global/tree.css                    (skin/tree.css)
++   skin/classic/global/contents.rdf                (skin/contents.rdf)
 +   skin/classic/communicator/communicator.css      (skin/communicator.css)
 +   skin/classic/messenger/primaryToolbar.css       (skin/primaryToolbar.css)
 +   skin/classic/messenger/accountCentral.css       (skin/accountCentral.css)

mail/base/skin/contents.rdf

@@ -0,0 +1,31 @@
+<?xml version="1.0"?>
+
+<RDF:RDF xmlns:RDF="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+         xmlns:chrome="http://www.mozilla.org/rdf/chrome#">
+
+  <!-- List all the skins being supplied by this theme -->
+  <RDF:Seq about="urn:mozilla:skin:root">
+    <RDF:li resource="urn:mozilla:skin:classic/1.0" />
+  </RDF:Seq>
+
+  <!-- classic Information -->
+  <RDF:Description about="urn:mozilla:skin:classic/1.0"
+        chrome:displayName="Mozilla Thunderbird"
+        chrome:accessKey="P"
+        chrome:author="mozilla.org"
+        chrome:authorURL="http://www.mozilla.org/projects/thunderbird/"
+        chrome:description="This is the default Mozilla Thunderbird theme. Select this theme to return to the original appearance."
+        chrome:name="classic/1.0"
+        chrome:image="Preview.png">
+    <chrome:packages>
+      <RDF:Seq about="urn:mozilla:skin:classic/1.0:packages">
+        <RDF:li resource="urn:mozilla:skin:classic/1.0:global"/>
+      </RDF:Seq>
+    </chrome:packages>
+  </RDF:Description>
+
+  <!-- Version Information.  State that we work only with major version 1 of this
+       package. -->
+  <RDF:Description about="urn:mozilla:skin:classic/1.0:global"
+    chrome:skinVersion="1.2"/>
+</RDF:RDF>