[Offline] Creates metadata store interface for offline pages

Offline pages metadata store:
* Creates interface for the store
* The following actions are available on the store:
  - AddOfflinePage,
  - RemoveOfflinePage,
  - Load,
* Updates to the components_unittests to include offline
  pages

BUG=491352

Review URL: https://codereview.chromium.org/1160283003

Cr-Commit-Position: refs/heads/master@{#333697}

1 files changed, 9 insertions, 1 deletions

diff --git a/components/offline_pages/offline_page_model.h b/components/offline_pages/offline_page_model.h
index 7e57a14..d32ace1 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;
@@ -15,12 +16,13 @@ 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.
 class OfflinePageModel : public KeyedService {
  public:
-  OfflinePageModel();
+  explicit OfflinePageModel(scoped_ptr<OfflinePageMetadataStore> store);
   ~OfflinePageModel() override;
 
   // KeyedService:
@@ -32,7 +34,13 @@ class OfflinePageModel : public KeyedService {
   // 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);
 };