#147448, optimize mailnews' modern theme for better performance.

r=varga, sr=sspitzer

suite/themes/modern/jar.mn

@@ -365,8 +365,6 @@ modern.jar:
   skin/modern/messenger/icons/server-remote-lock.gif               (messenger/icons/server-remote-lock.gif)
   skin/modern/messenger/icons/thread-closed.gif                    (messenger/icons/thread-closed.gif)
   skin/modern/messenger/icons/thread-new-closed.gif                (messenger/icons/thread-new-closed.gif)
-  skin/modern/messenger/icons/thread-new-open.gif                  (messenger/icons/thread-new-open.gif)
-  skin/modern/messenger/icons/thread-open.gif                      (messenger/icons/thread-open.gif)
   skin/modern/messenger/icons/threadcol-threaded.gif               (messenger/icons/threadcol-threaded.gif)
   skin/modern/messenger/icons/threadcol-unthreaded.gif             (messenger/icons/threadcol-unthreaded.gif)
   skin/modern/messenger/icons/thread-closed-eye.gif                (messenger/icons/thread-closed-eye.gif)
@@ -377,14 +375,6 @@ modern.jar:
   skin/modern/messenger/icons/thread-new-closed-kill.gif           (messenger/icons/thread-new-closed-kill.gif)
   skin/modern/messenger/icons/thread-new-closed-offl-eye.gif       (messenger/icons/thread-new-closed-offl-eye.gif)
   skin/modern/messenger/icons/thread-new-closed-offl-kill.gif      (messenger/icons/thread-new-closed-offl-kill.gif)
-  skin/modern/messenger/icons/thread-new-open-eye.gif              (messenger/icons/thread-new-open-eye.gif)
-  skin/modern/messenger/icons/thread-new-open-kill.gif             (messenger/icons/thread-new-open-kill.gif)
-  skin/modern/messenger/icons/thread-new-open-offl-eye.gif         (messenger/icons/thread-new-open-offl-eye.gif)
-  skin/modern/messenger/icons/thread-new-open-offl-kill.gif        (messenger/icons/thread-new-open-offl-kill.gif)
-  skin/modern/messenger/icons/thread-open-eye.gif                  (messenger/icons/thread-open-eye.gif)
-  skin/modern/messenger/icons/thread-open-kill.gif                 (messenger/icons/thread-open-kill.gif)
-  skin/modern/messenger/icons/thread-open-offl-eye.gif             (messenger/icons/thread-open-offl-eye.gif)
-  skin/modern/messenger/icons/thread-open-offl-kill.gif            (messenger/icons/thread-open-offl-kill.gif)
   skin/modern/messenger/icons/new-mail-alert.png                     (messenger/icons/new-mail-alert.png)
   skin/modern/messenger/icons/btn1.gif                             (messenger/icons/btn1.gif)
   skin/modern/messenger/messengercompose/messengercompose.css      (messenger/messengercompose/messengercompose.css)

suite/themes/modern/messenger/threadPane.css

@@ -111,18 +111,10 @@ treechildren:-moz-tree-image(threadCol, container) {
   list-style-image: url("chrome://messenger/skin/icons/thread-closed.gif");
 }
 
-treechildren:-moz-tree-image(threadCol, container, open) {
-  list-style-image: url("chrome://messenger/skin/icons/thread-open.gif");
-}
-
 treechildren:-moz-tree-image(threadCol, container, hasUnread) {
   list-style-image: url("chrome://messenger/skin/icons/thread-new-closed.gif");
 }
 
-treechildren:-moz-tree-image(threadCol, container, hasUnread, open) {
-  list-style-image: url("chrome://messenger/skin/icons/thread-new-open.gif");
-}
-
 /* ::::: new thread icons for watch and ignore ::::: */
 
 treechildren:-moz-tree-image(news, threadCol, container, watch) {
@@ -157,38 +149,6 @@ treechildren:-moz-tree-image(news, threadCol, container, hasUnread, ignore, offl
   list-style-image: url("chrome://messenger/skin/icons/thread-new-closed-offl-kill.gif");
 }
 
-treechildren:-moz-tree-image(news, threadCol, container, hasUnread, watch, open) {
-  list-style-image: url("chrome://messenger/skin/icons/thread-new-open-eye.gif");
-}
-
-treechildren:-moz-tree-image(news, threadCol, container, hasUnread, ignore, open) {
-  list-style-image: url("chrome://messenger/skin/icons/thread-new-open-kill.gif");
-}
-
-treechildren:-moz-tree-image(news, threadCol, container, hasUnread, watch, open, offline) {
-  list-style-image: url("chrome://messenger/skin/icons/thread-new-open-offl-eye.gif");
-}
-
-treechildren:-moz-tree-image(news, threadCol, container, hasUnread, ignore, open, offline) {
-  list-style-image: url("chrome://messenger/skin/icons/thread-new-open-offl-kill.gif");
-}
-
-treechildren:-moz-tree-image(news, threadCol, container, watch, open) {
-  list-style-image: url("chrome://messenger/skin/icons/thread-open-eye.gif");
-}
-
-treechildren:-moz-tree-image(news, threadCol, container, ignore, open) {
-  list-style-image: url("chrome://messenger/skin/icons/thread-open-kill.gif");
-}
-
-treechildren:-moz-tree-image(news, threadCol, container, watch, open, offline) {
-  list-style-image: url("chrome://messenger/skin/icons/thread-open-offl-eye.gif");
-}
-
-treechildren:-moz-tree-image(news, threadCol, container, ignore, open, offline) {
-  list-style-image: url("chrome://messenger/skin/icons/thread-open-offl-kill.gif");
-}
-
 /* ..... read column ..... */
 
 treecol.readColumnHeader {