Abstract history dependencies on bookmarks through HistoryClient

components/history/core/browser/history_client.h

+// Copyright 2014 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 COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_CLIENT_H_
+#define COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_CLIENT_H_
+
+#include <vector>
+
+#include "base/macros.h"
+#include "base/strings/string16.h"
+#include "url/gurl.h"
+
+namespace history {
+
+struct URLAndTitle {
+  GURL url;
+  base::string16 title;
+};
+
+// This class abstracts operations that depends on the embedder's environment,
+// e.g. Chrome.
+class HistoryClient {
+ public:
+  // Waits until the bookmarks have been loaded.
+  //
+  // Must not be called from the main thread.
+  virtual void BlockTillBookmarksLoaded();
+
+  // Returns true if the specified URL is bookmarked.
+  //
+  // If not on the main thread, then you must call BlockTillLoaded first.
+  virtual bool IsBookmarked(const GURL& url);
+
+  // Returns, by reference in |bookmarks|, the set of bookmarked urls and their
+  // titles. This returns the unique set of URLs. For example, if two bookmarks
+  // reference the same URL only one entry is added even if the title are not
+  // the same.
+  //
+  // If not on the main thread, then you must call BlockTillLoaded first.
+  virtual void GetBookmarks(std::vector<URLAndTitle>* bookmarks);
+
+ protected:
+  HistoryClient() {}
+  virtual ~HistoryClient() {}
+
+  DISALLOW_COPY_AND_ASSIGN(HistoryClient);
+};
+
+}  // namespace history
+
+#endif  // COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_CLIENT_H_