[MD Bookmarks] Add toasts.

chrome/browser/ui/webui/plural_string_handler.cc

+// Copyright 2017 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/ui/webui/plural_string_handler.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/values.h"
+#include "content/public/browser/web_ui.h"
+#include "ui/base/l10n/l10n_util.h"
+
+PluralStringHandler::PluralStringHandler() {}
+
+PluralStringHandler::~PluralStringHandler() {}
+
+void PluralStringHandler::RegisterMessages() {
+  web_ui()->RegisterMessageCallback(
+      "getPluralString", base::Bind(&PluralStringHandler::HandleGetPluralString,
+                                    base::Unretained(this)));
+}
+
+void PluralStringHandler::AddLocalizedString(const std::string& name, int id) {
+  name_to_id_[name] = id;
+}
+
+void PluralStringHandler::HandleGetPluralString(const base::ListValue* args) {
+  AllowJavascript();
+  CHECK_EQ(3U, args->GetSize());
+  const base::Value* callback_id;
+  CHECK(args->Get(0, &callback_id));
+
+  std::string message_name;
+  CHECK(args->GetString(1, &message_name));
+
+  int count;
+  CHECK(args->GetInteger(2, &count));
+
+  auto message_id_it = name_to_id_.find(message_name);
+  DCHECK(name_to_id_.end() != message_id_it);

[tsergeant, 2017/06/01 08:25:00]

Should this be a CHECK instead of a DCHECK? What gets returned to JS if this
happens? Surely passing a nonexistent message id is just as bad as passing no
message id at all.

[calamity, 2017/06/02 05:34:22]

Done.

+
+  ResolveJavascriptCallback(*callback_id,
+                            base::Value(l10n_util::GetPluralStringFUTF8(
+                                message_id_it->second, count)));
+}