Allow AppSearchProvider to provide recommendations.

ui/app_list/app_list_view_delegate.h

 // Copyright (c) 2012 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.
 
 #ifndef UI_APP_LIST_APP_LIST_VIEW_DELEGATE_H_
 #define UI_APP_LIST_APP_LIST_VIEW_DELEGATE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 63 matching lines @@
 
   // Gets the SpeechUIModel for the app list. Owned by the AppListViewDelegate.
   virtual SpeechUIModel* GetSpeechUI() = 0;
 
   // Gets a path to a shortcut for the given app. Returns asynchronously as the
   // shortcut may not exist yet.
   virtual void GetShortcutPathForApp(
       const std::string& app_id,
       const base::Callback<void(const base::FilePath&)>& callback) = 0;
 
+  // Invoked to start a search query for recommendations. This populates
+  // AppListModel::SearchResults with the retrieved recommendations.
+  virtual void FetchRecommendations() = 0;
+
   // Invoked to start a new search. Delegate collects query input from
   // SearchBoxModel and populates SearchResults. Both models are sub models
   // of AppListModel.
   virtual void StartSearch() = 0;
 
   // Invoked to stop the current search.
   virtual void StopSearch() = 0;
 
   // Invoked to open the search result.
   virtual void OpenSearchResult(SearchResult* result,
@@ skipping 61 matching lines @@
   virtual bool ShouldCenterWindow() const = 0;
 
   // Adds/removes an observer for profile changes.
   virtual void AddObserver(AppListViewDelegateObserver* observer) {}
   virtual void RemoveObserver(AppListViewDelegateObserver* observer) {}
 };
 
 }  // namespace app_list
 
 #endif  // UI_APP_LIST_APP_LIST_VIEW_DELEGATE_H_