Update Multipreffer code.

src/privileged/multipreffer/api.js

@@ -2,17 +2,12 @@
 
 Cu.importGlobalProperties(["fetch"]);
 
-ChromeUtils.defineModuleGetter(this, "Services",
-  "resource://gre/modules/Services.jsm");
-ChromeUtils.defineModuleGetter(this, "ExtensionCommon",
-  "resource://gre/modules/ExtensionCommon.jsm");
 ChromeUtils.defineModuleGetter(this, "AddonManager",
   "resource://gre/modules/AddonManager.jsm");
 ChromeUtils.defineModuleGetter(this, "Preferences",
   "resource://gre/modules/Preferences.jsm");
 const DefaultPreferences = new Preferences({ defaultBranch: true });
 
-
 let gExtension;
 
 this.multipreffer = class extends ExtensionAPI {
@@ -29,6 +24,10 @@ this.multipreffer = class extends ExtensionAPI {
 };
 
 this.FirefoxHooks = {
+  // Default branch prefs can't be "reset" since they ARE
+  // (supposed to be) the defaults. So in order to reset
+  // them at cleanup, we cache the values of our target
+  // prefs in this object before modifying them.
   _oldDefaultValues: {},
   async studyReady(studyInfo) {
     // Called every time the add-on is loaded.
@@ -43,62 +42,57 @@ this.FirefoxHooks = {
     const variationName =
       Preferences.get(
         "extensions.multipreffer.test.variationName", studyInfo.variation.name);
+
     const prefs = this.variations[variationName].prefs;
 
     for (const pref of Object.keys(prefs)) {
       let val = Preferences.get(pref);
       if (val === undefined) {
-        // If undefined, save it as an empty string.
+        // If undefined, save it as a false-y value.
         // This is the best we can do to reset it at cleanup
         // since there's no way to clear the value of a pref
         // on the default branch.
-        val = "";
+        switch (typeof prefs[pref]) {
+          case "string":
+            val = "";
+            break;
+          case "boolean":
+            val = false;
+            break;
+          case "number":
+            val = 0;
+            break;
+        }
       }
       this._oldDefaultValues[pref] = val;
     }
 
     DefaultPreferences.set(prefs);
-    this.recomputeCategoryPref();
+
     AddonManager.addAddonListener(this);
   },
 
+  /** Called when the add-on is being removed for any reason. */
   cleanup() {
-    // Called when the add-on is being removed for any reason.
     DefaultPreferences.set(this._oldDefaultValues);
-    this.recomputeCategoryPref();
-  },
-
-  recomputeCategoryPref() {
-    // BrowserGlue will recompute the category pref when the cookie behavior
-    // pref changes value, but only if the category pref is unset. So, we
-    // need to change the cookie behavior pref, which will recompute the
-    // category pref. Then, clear the newly recomputed category pref, and
-    // finally restore the cookie behavior pref again which will recompute
-    // the category pref in the correct state.
-    const cookieBehaviorValue =
-      Preferences.get("network.cookie.cookieBehavior");
-    const tempCookieBehaviorValue = cookieBehaviorValue === 4 ? 0 : 4;
-    Preferences.set("network.cookie.cookieBehavior", tempCookieBehaviorValue);
-    Preferences.reset("browser.contentblocking.category");
-    Preferences.set("network.cookie.cookieBehavior", cookieBehaviorValue);
+    AddonManager.removeAddonListener(this);
   },
 
   onUninstalling(addon) {
-    this.handleDisableOrUninstall(addon);
-  },
-
-  onDisabled(addon) {
-    this.handleDisableOrUninstall(addon);
-  },
-
-  async handleDisableOrUninstall(addon) {
     if (addon.id !== gExtension.id) {
       return;
     }
     this.cleanup();
-    AddonManager.removeAddonListener(this);
-    // This is needed even for onUninstalling, because it nukes the addon
-    // from UI. If we don't do this, the user has a chance to "undo".
+
+    // This is needed because it nukes the addon from about:addons UI.
+    // If we don't do this, the user has a chance to "undo".
     addon.uninstall();
   },
+
+  onDisabled(addon) {
+    if (addon.id !== gExtension.id) {
+      return;
+    }
+    this.cleanup();
+  },
 };