Bug 1321947 - Add "Don't Allow" button to add-on installation permission doorhanger to make it dismissible. r=florian

MozReview-Commit-ID: FwRmLOMA1Zr

--HG--
extra : rebase_source : 761363ce4eb203fde9e30a2f4ee60ccbdb3da14f

browser/base/content/browser-addons.js

@@ -281,11 +281,16 @@ const gXPInstallObserver = {
           installInfo.install();
         }
       };
+      let secondaryAction = {
+        label: gNavigatorBundle.getString("xpinstallPromptMessage.dontAllow"),
+        accessKey: gNavigatorBundle.getString("xpinstallPromptMessage.dontAllow.accesskey"),
+        callback: () => {},
+      };
 
       secHistogram.add(Ci.nsISecurityUITelemetry.WARNING_ADDON_ASKING_PREVENTED);
       let popup = PopupNotifications.show(browser, notificationID,
                                           messageString, anchorID,
-                                          action, null, options);
+                                          action, [secondaryAction], options);
       removeNotificationOnEnd(popup, installInfo.installs);
       break; }
     case "addon-install-started": {

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

@@ -21,6 +21,8 @@ contextMenuSearch.accesskey=S
 bookmarkAllTabsDefault=[Folder Name]
 
 xpinstallPromptMessage=%S prevented this site from asking you to install software on your computer.
+xpinstallPromptMessage.dontAllow=Don’t Allow
+xpinstallPromptMessage.dontAllow.accesskey=D
 xpinstallPromptAllowButton=Allow
 # Accessibility Note:
 # 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)