Abstract history dependencies on bookmarks through HistoryClient

chrome/browser/history/chrome_history_client.cc

+// 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.
+
+#include "chrome/browser/history/chrome_history_client.h"
+
+#include "chrome/browser/bookmarks/bookmark_model_factory.h"
+#include "chrome/browser/history/history_service.h"
+#include "components/bookmarks/browser/bookmark_model.h"
+
+namespace history {
+
+ChromeHistoryClient::ChromeHistoryClient(Profile* profile)
+    : bookmark_model_(NULL) {
+  history_service_.reset(new HistoryService(this, profile));
+  bookmark_model_ = BookmarkModelFactory::GetForProfile(profile);
+}
+
+void ChromeHistoryClient::BlockTillBookmarksLoaded() {
+  if (bookmark_model_)
+    bookmark_model_->BlockTillLoaded();
+}
+
+bool ChromeHistoryClient::IsBookmarked(const GURL& url) {
+  return bookmark_model_ && bookmark_model_->IsBookmarked(url);
+}
+
+void ChromeHistoryClient::GetBookmarks(std::vector<URLAndTitle>* bookmarks) {
+  if (bookmark_model_) {
+    std::vector<BookmarkModel::URLAndTitle> bookmarks_url_and_title;
+    bookmark_model_->GetBookmarks(&bookmarks_url_and_title);
+
+    bookmarks->reserve(bookmarks->size() + bookmarks_url_and_title.size());
+    for (size_t i = 0; i < bookmarks_url_and_title.size(); ++i) {
+      URLAndTitle value = {
+        bookmarks_url_and_title[i].url,
+        bookmarks_url_and_title[i].title,
+      };
+      bookmarks->push_back(value);
+    }
+  }
+}
+
+void ChromeHistoryClient::Shutdown() {
+  // It's possible that bookmarks haven't loaded and history is waiting for
+  // bookmarks to complete loading. In such a situation history can't shutdown
+  // (meaning if we invoked history_service_->Cleanup now, we would
+  // deadlock). To break the deadlock we tell BookmarkModel it's about to be
+  // deleted so that it can release the signal history is waiting on, allowing
+  // history to shutdown (history_service_->Cleanup to complete). In such a
+  // scenario history sees an incorrect view of bookmarks, but it's better
+  // than a deadlock.
+  if (bookmark_model_)
+    bookmark_model_->Shutdown();
+
+  history_service_->Cleanup();
+}
+
+}  // namespace history