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"
 
-ChromeHistoryClient::ChromeHistoryClient() {
+#include "base/logging.h"
+#include "components/bookmarks/browser/bookmark_model.h"
+
+ChromeHistoryClient::ChromeHistoryClient(BookmarkModel* bookmark_model)
+    : bookmark_model_(bookmark_model) {
+  DCHECK(bookmark_model_);
 }
+
+void ChromeHistoryClient::BlockUntilBookmarksLoaded() {
+  bookmark_model_->BlockTillLoaded();
+}
+
+bool ChromeHistoryClient::IsBookmarked(const GURL& url) {
+  return bookmark_model_->IsBookmarked(url);
+}
+
+void ChromeHistoryClient::GetBookmarks(
+    std::vector<history::URLAndTitle>* bookmarks) {
+  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) {
+    history::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 HistoryService::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 (HistoryService::Cleanup to complete). In such a scenario history
+  // sees an incorrect view of bookmarks, but it's better than a deadlock.
+  bookmark_model_->Shutdown();
+}