cros: Break BaseScreenHandler into two classes.

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

 // Copyright (c) 2012 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_CHROMEOS_LOGIN_BASE_SCREEN_HANDLER_H_
 #define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_BASE_SCREEN_HANDLER_H_
 
-#include <string>
-
-#include "base/bind.h"
-#include "base/bind_helpers.h"
-#include "base/callback.h"
 #include "base/macros.h"
 #include "chrome/browser/chromeos/login/oobe_screen.h"
-#include "chrome/browser/chromeos/login/screens/model_view_channel.h"
-#include "components/login/base_screen_handler_utils.h"
-#include "content/public/browser/web_ui.h"
-#include "content/public/browser/web_ui_message_handler.h"
-#include "ui/gfx/native_widget_types.h"
-
-namespace base {
-class DictionaryValue;
-class ListValue;
-}
-
-namespace login {
-class LocalizedValuesBuilder;
-}
+#include "chrome/browser/ui/webui/chromeos/login/base_webui_handler.h"
 
 namespace chromeos {
 
-class BaseScreen;
-class OobeUI;
-
-// Base class for the OOBE/Login WebUI handlers.
-class BaseScreenHandler : public content::WebUIMessageHandler,
-                          public ModelViewChannel {
+// Base class for the OOBE/Login WebUI handlers which provide methods specific
+// to a particular OobeScreen.
+class BaseScreenHandler : public BaseWebUIHandler {
  public:
-  BaseScreenHandler();
+  explicit BaseScreenHandler(OobeScreen oobe_screen);
   ~BaseScreenHandler() override;
 
-  // Gets localized strings to be used on the page.
-  void GetLocalizedStrings(
-      base::DictionaryValue* localized_strings);
-
-  // WebUIMessageHandler implementation:
-  void RegisterMessages() override;
-
-  // ModelViewChannel implementation:
-  void CommitContextChanges(const base::DictionaryValue& diff) override;
-
-  // This method is called when page is ready. It propagates to inherited class
-  // via virtual Initialize() method (see below).
-  void InitializeBase();
-
-  void set_async_assets_load_id(const std::string& async_assets_load_id) {
-    async_assets_load_id_ = async_assets_load_id;
-  }
-  const std::string& async_assets_load_id() const {
-    return async_assets_load_id_;
-  }
-
-  // Set the prefix used when running CallJs with a method. For example,
-  //    set_call_js_prefix("Oobe")
-  //    CallJs("lock") -> Invokes JS global named "Oobe.lock"
-  void set_call_js_prefix(const std::string& prefix) {
-    js_screen_path_prefix_ = prefix + ".";
-  }
-
- protected:
-  // All subclasses should implement this method to provide localized values.
-  virtual void DeclareLocalizedValues(
-      ::login::LocalizedValuesBuilder* builder) = 0;
-
-  // All subclasses should implement this method to register callbacks for JS
-  // messages.
-  //
-  // TODO (ygorshenin, crbug.com/433797): make this method purely vrtual when
-  // all screens will be switched to use ScreenContext.
-  virtual void DeclareJSCallbacks() {}
-
-  // Subclasses can override these methods to pass additional parameters
-  // to loadTimeData. Generally, it is a bad approach, and it should be replaced
-  // with Context at some point.
-  virtual void GetAdditionalParameters(base::DictionaryValue* parameters);
-
-  // Shortcut for calling JS methods on WebUI side.
-  void CallJS(const std::string& method);
-
-  template<typename A1>
-  void CallJS(const std::string& method, const A1& arg1) {
-    web_ui()->CallJavascriptFunctionUnsafe(FullMethodPath(method),
-                                           ::login::MakeValue(arg1));
-  }
-
-  template<typename A1, typename A2>
-  void CallJS(const std::string& method, const A1& arg1, const A2& arg2) {
-    web_ui()->CallJavascriptFunctionUnsafe(FullMethodPath(method),
-                                           ::login::MakeValue(arg1),
-                                           ::login::MakeValue(arg2));
-  }
-
-  template<typename A1, typename A2, typename A3>
-  void CallJS(const std::string& method,
-              const A1& arg1,
-              const A2& arg2,
-              const A3& arg3) {
-    web_ui()->CallJavascriptFunctionUnsafe(
-        FullMethodPath(method), ::login::MakeValue(arg1),
-        ::login::MakeValue(arg2), ::login::MakeValue(arg3));
-  }
-
-  template<typename A1, typename A2, typename A3, typename A4>
-  void CallJS(const std::string& method,
-              const A1& arg1,
-              const A2& arg2,
-              const A3& arg3,
-              const A4& arg4) {
-    web_ui()->CallJavascriptFunctionUnsafe(
-        FullMethodPath(method), ::login::MakeValue(arg1),
-        ::login::MakeValue(arg2), ::login::MakeValue(arg3),
-        ::login::MakeValue(arg4));
-  }
-
-  // Shortcut methods for adding WebUI callbacks.
-  template<typename T>
-  void AddRawCallback(const std::string& name,
-                      void (T::*method)(const base::ListValue* args)) {
-    web_ui()->RegisterMessageCallback(
-        name,
-        base::Bind(method, base::Unretained(static_cast<T*>(this))));
-  }
-
-  template<typename T, typename... Args>
-  void AddCallback(const std::string& name, void (T::*method)(Args...)) {
-    base::Callback<void(Args...)> callback =
-        base::Bind(method, base::Unretained(static_cast<T*>(this)));
-    web_ui()->RegisterMessageCallback(
-        name, base::Bind(&::login::CallbackWrapper<Args...>, callback));
-  }
-
-  template <typename Method>
-  void AddPrefixedCallback(const std::string& unprefixed_name,
-                           const Method& method) {
-    AddCallback(FullMethodPath(unprefixed_name), method);
-  }
-
-  // Called when the page is ready and handler can do initialization.
-  virtual void Initialize() = 0;
-
-  // Show selected WebUI |screen|.
-  void ShowScreen(OobeScreen screen);
-  // Show selected WebUI |screen|. Pass screen initialization using the |data|
-  // parameter.
-  void ShowScreenWithData(OobeScreen screen, const base::DictionaryValue* data);
-
-  // Returns the OobeUI instance.
-  OobeUI* GetOobeUI() const;
-
-  // Returns current visible OOBE screen.
-  OobeScreen GetCurrentScreen() const;
-
-  // Whether page is ready.
-  bool page_is_ready() const { return page_is_ready_; }
-
-  // Returns the window which shows us.
-  virtual gfx::NativeWindow GetNativeWindow();
-
-  void SetBaseScreen(BaseScreen* base_screen);
+  OobeScreen oobe_screen() const { return oobe_screen_; }

[Alexander Alekseev, 2017/03/01 01:53:40]

It looks like BaseScreenHandler is now empty and can be removed.
So you are probably renaming it to BaseWebUiHandler, aren't you?

[jdufault, 2017/03/01 17:53:51]

I'd like to move more logic from BaseWebUIHandler to BaseScreenHandler, but it
is very challenging to do so at the moment.

The idea is that BaseScreenHandler is derived by any WebUI class directly
associated with an OobeScreen. Other WebUI classes (like the one for oobe or the
login page) are not associated with a specific OobeScreen so they derive from
BaseWebUIHandler.

 
  private:
-  // Returns full name of JS method based on screen and method
-  // names.
-  std::string FullMethodPath(const std::string& method) const;
-
-  // Handles user action.
-  void HandleUserAction(const std::string& action_id);
-
-  // Handles situation when screen context is changed.
-  void HandleContextChanged(const base::DictionaryValue* diff);
-
-  // Keeps whether page is ready.
-  bool page_is_ready_ = false;
-
-  BaseScreen* base_screen_ = nullptr;
-
-  // Full name of the corresponding JS screen object. Can be empty, if
-  // there are no corresponding screen object or several different
-  // objects.
-  std::string js_screen_path_prefix_;
-
-  // The string id used in the async asset load in JS. If it is set to a
-  // non empty value, the Initialize will be deferred until the underlying load
-  // is finished.
-  std::string async_assets_load_id_;
-
-  // Pending changes to context which will be sent when the page will be ready.
-  base::DictionaryValue pending_context_changes_;
+  // OobeScreen that this handler corresponds to.
+  OobeScreen oobe_screen_ = OobeScreen::SCREEN_UNKNOWN;
 
   DISALLOW_COPY_AND_ASSIGN(BaseScreenHandler);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_BASE_SCREEN_HANDLER_H_