Bug 580956: 'Undo Close Tab' should not be hidden when there are none to undo. r=dao

--HG--
extra : rebase_source : ae5bdfa5f4c169127f4b59e805a333ff148c3ca2

browser/base/content/browser.js

@@ -7766,13 +7766,11 @@ var TabContextMenu = {
       menuItems[i].disabled = disabled;
 
     // Session store
-    // XXXzeniko should't we just disable this item as we disable
-    // the tabbrowser-multiple items above - for consistency?
-    document.getElementById("context_undoCloseTab").hidden =
+    document.getElementById("context_undoCloseTab").disabled =
       Cc["@mozilla.org/browser/sessionstore;1"].
       getService(Ci.nsISessionStore).
       getClosedTabCount(window) == 0;
-      
+
     // Only one of pin/unpin should be visible
     document.getElementById("context_pinTab").hidden = this.contextTab.pinned;
     document.getElementById("context_unpinTab").hidden = !this.contextTab.pinned;

browser/base/content/browser.xul

@@ -140,7 +140,7 @@
       <menuitem id="context_undoCloseTab"
                 label="&undoCloseTab.label;"
                 accesskey="&undoCloseTab.accesskey;"
-                command="History:UndoCloseTab"/>
+                observes="History:UndoCloseTab"/>
       <menuitem id="context_closeTab" label="&closeTab.label;" accesskey="&closeTab.accesskey;"
                 oncommand="gBrowser.removeTab(TabContextMenu.contextTab);"/>
     </menupopup>

browser/base/content/test/Makefile.in

@@ -137,6 +137,7 @@ _BROWSER_FILES = \
                  browser_bug562649.js \
                  browser_bug563588.js \
                  browser_bug577121.js \
+                 browser_bug580956.js \
                  browser_contextSearchTabPosition.js \
                  browser_ctrlTab.js \
                  browser_discovery.js \

browser/base/content/test/browser_bug580956.js

@@ -0,0 +1,27 @@
+function numClosedTabs()
+  Cc["@mozilla.org/browser/sessionstore;1"].
+    getService(Ci.nsISessionStore).
+    getClosedTabCount(window);
+
+function isUndoCloseEnabled() {
+  document.popupNode = gBrowser.tabs[0];
+  TabContextMenu.updateContextMenu(document.getElementById("tabContextMenu"));
+  return !document.getElementById("context_undoCloseTab").disabled;
+}
+
+function test() {
+  waitForExplicitFinish();
+
+  gPrefService.setIntPref("browser.sessionstore.max_tabs_undo", 0);
+  gPrefService.clearUserPref("browser.sessionstore.max_tabs_undo");
+  is(numClosedTabs(), 0, "There should be 0 closed tabs.");
+  ok(!isUndoCloseEnabled(), "Undo Close Tab should be disabled.");
+
+  var tab = gBrowser.addTab("http://mochi.test:8888/");
+  var browser = gBrowser.getBrowserForTab(tab);
+  browser.addEventListener("load", function() {
+    gBrowser.removeTab(tab);
+    ok(isUndoCloseEnabled(), "Undo Close Tab should be enabled.");
+    finish();
+  }, true);
+}