Abstract history dependencies on bookmarks through HistoryClient

components/history/core/browser/history_client.h

Index: components/history/core/browser/history_client.h
diff --git a/components/history/core/browser/history_client.h b/components/history/core/browser/history_client.h
index cc2da5845823c416361f47b1dabe772afc642c84..370d723392b5b90e232d37ec15fd97eed74956b1 100644
--- a/components/history/core/browser/history_client.h
+++ b/components/history/core/browser/history_client.h
@@ -5,17 +5,45 @@
 #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 "components/keyed_service/core/keyed_service.h"
+#include "url/gurl.h"
 
 namespace history {
 
+struct URLAndTitle {
+  GURL url;
+  base::string16 title;
+};
+
 // This class abstracts operations that depend on the embedder's environment,
 // e.g. Chrome.
 class HistoryClient : public KeyedService {
- protected:
-  HistoryClient() {}
+ public:
+  HistoryClient();
 
+  // Waits until the bookmarks have been loaded.
+  //
+  // Must not be called from the main thread.
+  virtual void BlockUntilBookmarksLoaded();
+
+  // Returns true if the specified URL is bookmarked.
+  //
+  // If not on the main thread, then BlockUntilBookmarksLoaded must be called.
+  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 BlockUntilBookmarksLoaded must be called.
+  virtual void GetBookmarks(std::vector<URLAndTitle>* bookmarks);
+
+ protected:
   DISALLOW_COPY_AND_ASSIGN(HistoryClient);
 };