cros: Break BaseScreenHandler into two classes.

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

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// 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.
 
-#ifndef CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_BASE_SCREEN_HANDLER_H_
-#define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_BASE_SCREEN_HANDLER_H_
+#ifndef CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_BASE_WEBUI_HANDLER_H_
+#define CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_BASE_WEBUI_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;
 }
 
 namespace chromeos {
 
 class BaseScreen;
 class OobeUI;
 
 // A helper class to store deferred Javascript calls, shared by subclasses of
-// BaseScreenHandler.
+// BaseWebUIHandler.
 class JSCallsContainer {
  public:
   JSCallsContainer();
   ~JSCallsContainer();
 
   // Used to decide whether the JS call should be deferred.
   bool is_initialized() { return is_initialized_; }
 
   // Used to mark the instance as intialized.
   void mark_initialized() { is_initialized_ = true; }
 
   // Used to add deferred calls to.
   std::vector<base::Closure>& deferred_js_calls() { return deferred_js_calls_; }
 
  private:
   // Whether the instance is initialized.
   //
   // The instance becomes initialized after the corresponding message is
   // received from Javascript side.
   bool is_initialized_ = false;
 
   // Javascript calls that have been deferred while the instance was not
   // initialized yet.
   std::vector<base::Closure> deferred_js_calls_;
 };
 
-// Base class for the OOBE/Login WebUI handlers.
-class BaseScreenHandler : public content::WebUIMessageHandler,
-                          public ModelViewChannel {
+// Base class for all oobe/login WebUI handlers. These handlers are the binding
+// layer that allow the C++ and JavaScript code to communicate.
+//
+// If the deriving type is associated with a specific OobeScreen, it should
+// derive from BaseScreenHandler instead of BaseWebUIHandler.
+//
+// TODO(jdufault): Move all OobeScreen related concepts out of BaseWebUIHandler
+// and into BaseScreenHandler.
+class BaseWebUIHandler : public content::WebUIMessageHandler,
+                         public ModelViewChannel {
  public:
-  BaseScreenHandler();
-  explicit BaseScreenHandler(JSCallsContainer* js_calls_container);
-  ~BaseScreenHandler() override;
+  BaseWebUIHandler();
+  explicit BaseWebUIHandler(JSCallsContainer* js_calls_container);
+  ~BaseWebUIHandler() override;
 
   // Gets localized strings to be used on the page.
-  void GetLocalizedStrings(
-      base::DictionaryValue* localized_strings);
+  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 + ".";
   }
 
+  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_;
+  }
+
  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>
+  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>
+  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>
+  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>
+  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));
   }
 
   template <typename... Args>
   void CallJSOrDefer(const std::string& function_name, const Args&... args) {
     DCHECK(js_calls_container_);
     if (js_calls_container_->is_initialized()) {
       CallJS(function_name, args...);
     } else {
       // Note that std::conditional is used here in order to obtain a sequence
       // of base::Value types with the length equal to sizeof...(Args); the C++
       // template parameter pack expansion rules require that the name of the
       // parameter pack appears in the pattern, even though the elements of the
       // Args pack are not actually in this code.
       js_calls_container_->deferred_js_calls().push_back(base::Bind(
-          &BaseScreenHandler::ExecuteDeferredJSCall<
+          &BaseWebUIHandler::ExecuteDeferredJSCall<
               typename std::conditional<true, base::Value, Args>::type...>,
           base::Unretained(this), function_name,
           base::Passed(::login::MakeValue(args).CreateDeepCopy())...));
     }
   }
 
   // Executes Javascript calls that were deferred while the instance was not
   // initialized yet.
   void ExecuteDeferredJSCalls();
 
   // Shortcut methods for adding WebUI callbacks.
-  template<typename T>
+  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))));
+        name, base::Bind(method, base::Unretained(static_cast<T*>(this))));
   }
 
-  template<typename T, typename... Args>
+  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) {
@@ skipping 57 matching lines @@
   // 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_;
 
   JSCallsContainer* js_calls_container_ = nullptr;  // non-owning pointers.
 
-  DISALLOW_COPY_AND_ASSIGN(BaseScreenHandler);
+  DISALLOW_COPY_AND_ASSIGN(BaseWebUIHandler);
 };
 
 }  // namespace chromeos
 
-#endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_BASE_SCREEN_HANDLER_H_
+#endif  // CHROME_BROWSER_UI_WEBUI_CHROMEOS_LOGIN_BASE_WEBUI_HANDLER_H_