WebUI: Allow rejecting a promise that is returned from cr.sendWithPromise().

chrome/browser/ui/webui/settings/md_settings_ui.h

 // Copyright (c) 2015 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 CHROME_BROWSER_UI_WEBUI_SETTINGS_MD_SETTINGS_UI_H_
 #define CHROME_BROWSER_UI_WEBUI_SETTINGS_MD_SETTINGS_UI_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 11 matching lines @@
 class SettingsPageUIHandler : public content::WebUIMessageHandler {
  public:
   SettingsPageUIHandler();
   ~SettingsPageUIHandler() override;
 
   // WebUIMessageHandler implementation.
   void RegisterMessages() override {}
 
  protected:
   // Helper method for responding to JS requests initiated with
-  // cr.sendWithPromise().
+  // cr.sendWithPromise(). |is_success| indicates whether the promise will be
+  // resolved or rejected.
   void CallJavascriptCallback(const base::Value& callback_id,
+                              bool is_success,
                               const base::Value& response);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SettingsPageUIHandler);
 };
 
 // The WebUI handler for chrome://md-settings.
 class MdSettingsUI : public content::WebUIController,
                      public content::WebContentsObserver {
  public:
@@ skipping 14 matching lines @@
   void AddSettingsPageUIHandler(content::WebUIMessageHandler* handler);
 
   base::Time load_start_time_;
 
   DISALLOW_COPY_AND_ASSIGN(MdSettingsUI);
 };
 
 }  // namespace settings
 
 #endif  // CHROME_BROWSER_UI_WEBUI_SETTINGS_MD_SETTINGS_UI_H_