Postpone JS calls from CoreOobeHandler until the JS side gets initialized

chrome/browser/ui/webui/chromeos/login/core_oobe_handler.h

Index: chrome/browser/ui/webui/chromeos/login/core_oobe_handler.h
diff --git a/chrome/browser/ui/webui/chromeos/login/core_oobe_handler.h b/chrome/browser/ui/webui/chromeos/login/core_oobe_handler.h
index 879daa85aebb8a3fe537661f8d393d0f654ecd62..bbfdb5936f472789b375acb046afd288f39f3416 100644
--- a/chrome/browser/ui/webui/chromeos/login/core_oobe_handler.h
+++ b/chrome/browser/ui/webui/chromeos/login/core_oobe_handler.h
@@ -5,9 +5,13 @@
 #ifndef CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_CORE_OOBE_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_CORE_OOBE_HANDLER_H_
 
+#include <memory>
 #include <string>
+#include <vector>
 
+#include "base/callback.h"
 #include "base/macros.h"
+#include "base/values.h"
 #include "chrome/browser/chromeos/accessibility/accessibility_manager.h"
 #include "chrome/browser/chromeos/login/screens/core_oobe_actor.h"
 #include "chrome/browser/chromeos/login/version_info_updater.h"
@@ -70,6 +74,23 @@ class CoreOobeHandler : public BaseScreenHandler,
   void UpdateShutdownAndRebootVisibility(bool reboot_on_shutdown);
 
  private:
+  // Calls javascript method.
+  //
+  // Note that the Args template parameter pack should consist of types
+  // convertible to base::Value.
+  template <typename... Args>
+  void ExecuteDeferredJSCall(const std::string& function_name,
+                             std::unique_ptr<Args>... args);
+
+  // Calls javascript method if the instance is already initialized, or defers
+  // the call until it gets initialized.
+  template <typename... Args>
+  void CallJSOrDefer(const std::string& function_name, const Args&... args);
+
+  // Executes javascript calls that were deferred while the instance was not
+  // initialized yet.
+  void ExecuteDeferredJSCalls();
+
   // CoreOobeActor implementation:
   void ShowSignInError(int login_attempts,
                        const std::string& error_text,
@@ -135,6 +156,16 @@ class CoreOobeHandler : public BaseScreenHandler,
   void OnAccessibilityStatusChanged(
       const AccessibilityStatusEventDetails& details);
 
+  // Whether the instance is initialized.
+  //
+  // The instance becomes initialized after the corresponding message is
+  // received from javascript side.
+  bool is_initialized_;
+
+  // Javascript calls that have been deferred while the instance was not
+  // initialized yet.
+  std::vector<base::Closure> deferred_js_calls_;
+
   // Owner of this handler.
   OobeUI* oobe_ui_;