[Offline] Creates metadata store interface for offline pages

components/offline_pages/offline_page_model.h

Index: components/offline_pages/offline_page_model.h
diff --git a/components/offline_pages/offline_page_model.h b/components/offline_pages/offline_page_model.h
index 7e57a14cb60035b1e6bfcc7679b8cbbd32cba053..f228caeb9b3bdf591edfb80662840a1e6744e7c0 100644
--- a/components/offline_pages/offline_page_model.h
+++ b/components/offline_pages/offline_page_model.h
@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
 #include "components/keyed_service/core/keyed_service.h"
 
 class GURL;
@@ -15,6 +16,7 @@ class GURL;
 namespace offline_pages {
 
 struct OfflinePageItem;
+class OfflinePageMetadataStore;
 
 // Serivce for saving pages offline, storing the offline copy and metadata, and
 // retrieving them upon request.
@@ -26,13 +28,23 @@ class OfflinePageModel : public KeyedService {
   // KeyedService:
   void Shutdown() override;
 
+  // Initializes the offline page model with a store to use for persisting
+  // offline page metadata.
+  void Initialize(scoped_ptr<OfflinePageMetadataStore> store);
+
   // Saves the page loaded in the web contents offline.
   void SavePageOffline(const GURL& url);
 
   // Gets a set of all offline pages metadata.
   std::vector<OfflinePageItem> GetAllOfflinePages();
 
+  // Methods for testing only:
+  OfflinePageMetadataStore* GetStoreForTesting();
+
  private:
+  // Persistent store for offline page metadata.
+  scoped_ptr<OfflinePageMetadataStore> store_;
+
   DISALLOW_COPY_AND_ASSIGN(OfflinePageModel);
 };