Addressing review comments.

src/js/ProviderManager.js

@@ -13,43 +13,15 @@ const ProviderManager = {
 
   _initialized: false,
 
-  get initialized() {
-    return this._initialized;
-  },
-
-  set initialized(initialized) {
-    this._initialized = initialized;
-  },
-
   init: async(function*(requestURL) {
-    if (!ProviderManager.initialized) {
+    if (!ProviderManager._initialized) {
       yield DirectoryLinksProvider.init(requestURL);
       Links.addProvider(PlacesProvider);
       Links.addProvider(DirectoryLinksProvider);
       yield gUserDatabase.init({"pinnedLinks": [], "blockedLinks": []});
       yield gPinnedLinks.init();
       yield gBlockedLinks.init();
-      ProviderManager.initialized = true;
+      ProviderManager._initialized = true;
     }
   }),
-
-  /**
-   * Extract a "site" from a url in a way that multiple urls of a "site" returns
-   * the same "site."
-   *
-   * @param {String} url Url spec string
-   * @return {String} The "site" string
-   */
-  extractSite(url) {
-    var host = "";
-    try {
-      // Note that URL interface might throw for non-standard urls.
-      host = new URL(url).host;
-    } catch (ex) {
-      return "";
-    }
-
-    // Strip off common subdomains of the same site (e.g., www, load balancer)
-    return host.replace(/^(m|mobile|www\d*)\./, "");
-  },
 };

src/js/directoryLinksProvider.js

@@ -2,16 +2,16 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
  /*jshint worker:true*/
- /*globals CacheTasks, async, ProviderManager, Links*/
+ /*globals CacheTasks, async, Links*/
 "use strict";
 
-// The const that tells where to obtain directory links
-const PREF_DIRECTORY_SOURCE = "https://tiles.services.mozilla.com/v3/links/fetch/en-US/nightly";
+(function(exports) {
+  // The const that tells where to obtain directory links
+  const PREF_DIRECTORY_SOURCE = "https://tiles.services.mozilla.com/v3/links/fetch/en-US/nightly";
 
-// The frecency of a directory link
-const DIRECTORY_FRECENCY = 1000;
+  // The frecency of a directory link
+  const DIRECTORY_FRECENCY = 1000;
 
-(function(exports) {
   /**
    * Emits notifications to PlacesProvider and Links
    */
@@ -43,16 +43,16 @@ const DIRECTORY_FRECENCY = 1000;
     getEnhancedLink(link) {
       // Use the provided link if it's already enhanced
       return link.enhancedImageURI && link ? link :
-             this._enhancedLinks.get(ProviderManager.extractSite(link.url));
+             this._enhancedLinks.get(Links.extractSite(link.url));
     },
 
     _cacheSuggestedLinks(link) {
       // Don't cache links that don't have the expected 'frecent_sites'
-      //jscs:disable requireCamelCaseOrUpperCaseIdentifiers
       if (!link.hasOwnProperty("frecent_sites")) {
         return;
       }
 
+      //jscs:disable requireCamelCaseOrUpperCaseIdentifiers
       for (let suggestedSite of link.frecent_sites) {
         let suggestedMap = this._suggestedLinks.get(suggestedSite) || new Map();
         suggestedMap.set(link.url, link);

src/js/links.js

@@ -14,7 +14,7 @@
  *   lastVisitDate: 1394678824766431,
  * }
  */
- /*globals gPinnedLinks, gBlockedLinks, ProviderManager, DirectoryLinksProvider*/
+ /*globals gPinnedLinks, gBlockedLinks, DirectoryLinksProvider*/
  /*jshint worker:true*/
 
 "use strict";
@@ -83,20 +83,20 @@
       let pinnedLinks = gPinnedLinks.links.slice();
       let links = this._getMergedProviderLinks();
 
-      let sites = pinnedLinks
+      // Create sitesMap to contain all the links at each base domain.
+      let sitesMap = pinnedLinks.concat(links)
         .filter(link => link)
-        .map(link => ProviderManager.extractSite(link.url))
-        .reduce((set, site) => set.add(site), new Set());
+        .reduce((map, link) => {
+          let site = this.extractSite(link.url);
+          return map.get(site) ? map : map.set(site, link);
+        }, new Map());
 
       // Filter blocked and pinned links and duplicate base domains.
       links = links.filter(function(link) {
-        let site = ProviderManager.extractSite(link.url);
-        if (!site || sites.has(site)) {
-          return false;
-        }
-        sites.add(site);
-
-        return !gBlockedLinks.isBlocked(link) && !gPinnedLinks.isPinned(link);
+        let site = Links.extractSite(link.url);
+        return !gBlockedLinks.isBlocked(link) &&
+               !gPinnedLinks.isPinned(link) &&
+               (site && (sitesMap.get(site).url === link.url));
       });
 
       // Try to fill the gaps between pinned links.
@@ -113,7 +113,7 @@
 
       pinnedLinks.forEach(link => {
         if (link) {
-          link.baseDomain = ProviderManager.extractSite(link.url);
+          link.baseDomain = this.extractSite(link.url);
         }
       });
 
@@ -132,7 +132,7 @@
         // Don't count blocked URLs.
         return;
       }
-      let site = ProviderManager.extractSite(link.url);
+      let site = this.extractSite(link.url);
       map.set(site, (map.get(site) || 0) + 1);
     },
 
@@ -190,6 +190,26 @@
       this._providers.set(aProvider, {});
       aProvider.addObserver(this);
     },
+
+    /**
+     * Extract a "site" from a url in a way that multiple urls of a "site" returns
+     * the same "site."
+     *
+     * @param {String} url Url spec string
+     * @return {String} The "site" string
+     */
+    extractSite(url) {
+      var host = "";
+      try {
+        // Note that URL interface might throw for non-standard urls.
+        host = new URL(url).host;
+      } catch (ex) {
+        return "";
+      }
+
+      // Strip off common subdomains of the same site (e.g., www, load balancer)
+      return host.replace(/^(m|mobile|www\d*)\./, "");
+    },
   };
   exports.Links = Links;
 }(self));

src/test/lib/cachetasks_spec.js

@@ -21,7 +21,7 @@ var tRequest = testType(new Request(""));
 describe("CacheTasks", function() {
   describe("deleteCaches() method", () => {
     it("should delete all caches when no argument is given.", async(function*() {
-      var cacheNames = [CACHENAME, "foo", "bar", "baz", "bing", "skeleton_cache", "ads_cache"];
+      var cacheNames = [CACHENAME, "foo", "bar", "baz", "bing"].concat(yield caches.keys());
       for (var name of cacheNames) {
         yield caches.open(name);
       }