Bug 954628 - Chat tooltips should contain the topic, r=clokep.

im/content/buddytooltip.xml

@@ -334,6 +334,8 @@
          this.removeAttribute("status");
          this.setBuddyIcon(null);
          this.addRow(this.bundle.GetStringFromName("buddy.account"), account.name);
+         if (aConv.topic)
+           this.addRow(this.bundle.GetStringFromName("conversation.topic"), aConv.topic);
          return true;
        ]]>
        </body>

im/locales/en-US/chrome/instantbird/buddytooltip.properties

@@ -6,3 +6,4 @@ buddy.screenname=Buddy
 buddy.loggedIn=Logged In
 buddy.account=Account
 contact.tags=Tags
+conversation.topic=Topic