Adding the chrome://copresence page

chrome/browser/ui/webui/copresence_ui_handler.h

+// 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.
+
+#ifndef CHROME_BROWSER_UI_WEBUI_COPRESENCE_UI_HANDLER_H_
+#define CHROME_BROWSER_UI_WEBUI_COPRESENCE_UI_HANDLER_H_
+
+#include "base/macros.h"
+#include "components/copresence/public/copresence_observer.h"
+#include "content/public/browser/web_ui_message_handler.h"
+
+namespace base {
+class ListValue;
+}
+
+namespace content {
+class WebUI;
+}
+
+namespace copresence {
+class CopresenceState;
+}
+
+// UI Handler for the copresence page.
+// TODO(crbug.com/444263): Write tests.
+class CopresenceUIHandler final : public content::WebUIMessageHandler,
+                                  public copresence::CopresenceObserver {
+ public:
+  explicit CopresenceUIHandler(content::WebUI* web_ui);
+  ~CopresenceUIHandler() override;
+
+ private:
+  // WebUIMessageHandler override.
+  void RegisterMessages() override;
+
+  // CopresenceObserver overrides.
+  void DirectivesUpdated() override;
+  void TokenTransmitted(const copresence::TransmittedToken& token) override;
+  void TokenReceived(const copresence::ReceivedToken& token) override;
+
+  // Handler to populate the page with its initial state.
+  void HandlePopulateState(const base::ListValue* args);
+
+  copresence::CopresenceState* state_;
+
+  DISALLOW_COPY_AND_ASSIGN(CopresenceUIHandler);
+};
+
+#endif  // CHROME_BROWSER_UI_WEBUI_COPRESENCE_UI_HANDLER_H_