Bug 310737: 1.0.x users have no way to re-enable software installation (message bar that appears when xpinstall.enabled is false points to removed UI). r=mconnor, ui=beltzner

browser/base/content/browser.js

@@ -582,13 +582,18 @@ const gXPInstallObserver = {
         }
         var messageString, buttonString, buttonAccesskeyString;
         if (!gPrefService.getBoolPref("xpinstall.enabled")) {
-          messageString = browserBundle.getFormattedString("xpinstallDisabledWarning",
-                                                           [brandShortName, host]);
-          buttonAccesskeyString = browserBundle.getString("xpinstallDisabledWarningButton.accesskey");
-          buttonString = browserBundle.getString("xpinstallDisabledWarningButton");
+          if (gPrefService.prefIsLocked("xpinstall.enabled")) {
+            messageString = browserBundle.getString("xpinstallDisabledMessageLocked");
+            buttonString = ""; // don't show the button
+          }
+          else {
+            messageString = browserBundle.getString("xpinstallDisabledMessage");
+            buttonString = browserBundle.getString("xpinstallDisabledButton");
+            buttonAccesskeyString = browserBundle.getString("xpinstallDisabledButton.accesskey");
+          }
           getBrowser().showMessage(browser, iconURL, messageString, buttonString,
                                    null, "xpinstall-install-edit-prefs",
-                                   null, "top", false, buttonAccesskeyString);
+                                   null, "top", true, buttonAccesskeyString);
         }
         else {
           messageString = browserBundle.getFormattedString(messageKey, [brandShortName, host]);
@@ -602,7 +607,7 @@ const gXPInstallObserver = {
       }
       break;
     case "xpinstall-install-edit-prefs":
-      openPreferences("paneContent");
+      gPrefService.setBoolPref("xpinstall.enabled", true);
       getBrowser().hideMessage(null, "top");
       break;
     case "xpinstall-install-edit-permissions":

browser/locales/en-US/chrome/browser/browser.properties

@@ -72,9 +72,10 @@ xpinstallWarningButton=Edit Options...
 # Be sure you do not choose an accesskey that is used elsewhere in the active context (e.g. main menu bar, submenu of the warning popup button)
 # See http://www.mozilla.org/access/keyboard/accesskey for details
 xpinstallWarningButton.accesskey=O
-xpinstallDisabledWarning=Software installation is currently disabled. Click Edit Options... to enable it and try again.
-xpinstallDisabledWarningButton=Edit Options...
-xpinstallDisabledWarningButton.accesskey=O
+xpinstallDisabledMessageLocked=Software installation has been disabled by your system administrator.
+xpinstallDisabledMessage=Software installation is currently disabled. Click Enable and try again.
+xpinstallDisabledButton=Enable
+xpinstallDisabledButton.accesskey=n
 themeWarning=To protect your computer, %S prevented this site (%S) from installing themes.
 themeWarningButton=Edit Options...
 popupWarning=%S prevented this site from opening a popup window.