Bug 1151507 - Warn users when unsigned add-ons have been disabled during startup. r=dtownsend

browser/components/nsBrowserGlue.js

@@ -955,12 +955,14 @@ BrowserGlue.prototype = {
     // With older versions of the extension installed, this load will fail
     // passively.
     aWindow.messageManager.loadFrameScript("resource://pdf.js/pdfjschildbootstrap.js", true);
+
 #ifdef NIGHTLY_BUILD
     // Registering Shumway bootstrap script the child processes.
     aWindow.messageManager.loadFrameScript("chrome://shumway/content/bootstrap-content.js", true);
     // Initializing Shumway (shall be run after child script registration).
     ShumwayUtils.init();
 #endif
+
 #ifdef XP_WIN
     // For windows seven, initialize the jump list module.
     const WINTASKBAR_CONTRACTID = "@mozilla.org/windows-taskbar;1";
@@ -1005,6 +1007,14 @@ BrowserGlue.prototype = {
 
     this._checkForOldBuildUpdates();
 
+    let disabledAddons = AddonManager.getStartupChanges(AddonManager.STARTUP_CHANGE_DISABLED);
+    for (let id of disabledAddons) {
+      if (AddonManager.getAddonByID(id).signedState <= AddonManager.SIGNEDSTATE_MISSING) {
+        this._notifyUnsignedAddonsDisabled();
+        break;
+      }
+    }
+
     this._firstWindowTelemetry(aWindow);
   },