Make InstallObserver methods not pure-virtual

chrome/browser/ui/app_list/recommended_apps.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/app_list/recommended_apps.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 80 matching lines @@
 
   const bool changed = apps_.size() != new_recommends.size() ||
       !std::equal(apps_.begin(), apps_.end(), new_recommends.begin());
   if (changed) {
     apps_.swap(new_recommends);
     FOR_EACH_OBSERVER(
         RecommendedAppsObserver, observers_, OnRecommendedAppsChanged());
   }
 }
 
-void RecommendedApps::OnBeginExtensionInstall(
-    const ExtensionInstallParams& params) {}
-
-void RecommendedApps::OnDownloadProgress(const std::string& extension_id,
-                                int percent_downloaded) {}
-
-void RecommendedApps::OnInstallFailure(const std::string& extension_id) {}
-
 void RecommendedApps::OnExtensionInstalled(
     const extensions::Extension* extension) {
   Update();
 }
 
 void RecommendedApps::OnExtensionLoaded(
     const extensions::Extension* extension) {
   Update();
 }
 
 void RecommendedApps::OnExtensionUnloaded(
     const extensions::Extension* extension) {
   Update();
 }
 
 void RecommendedApps::OnExtensionUninstalled(
     const extensions::Extension* extension) {
   Update();
 }
 
-void RecommendedApps::OnAppsReordered() {}
-
-void RecommendedApps::OnAppInstalledToAppList(
-    const std::string& extension_id) {}
-
-void RecommendedApps::OnShutdown() {}
-
 }  // namespace app_list