cros: Enable WebUILoginView reuse.

chrome/browser/chromeos/login/ui/webui_login_view.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_CHROMEOS_LOGIN_UI_WEBUI_LOGIN_VIEW_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_UI_WEBUI_LOGIN_VIEW_H_
 
 #include <map>
 #include <string>
 
@@ skipping 16 matching lines @@
 
 namespace views {
 class View;
 class WebView;
 class Widget;
 }
 
 namespace chromeos {
 
 class OobeUI;
+class SharedWebViewUsageHandle;
 
 // View used to render a WebUI supporting Widget. This widget is used for the
 // WebUI based start up and lock screens. It contains a WebView.
 class WebUILoginView : public views::View,
                        public content::WebContentsDelegate,
                        public content::NotificationObserver,
                        public ChromeWebModalDialogManagerDelegate,
                        public web_modal::WebContentsModalDialogHost {
  public:
+  struct WebViewSettings {
+    // URL of the WebView to preload and reuse across WebUILoginView instances.
+    GURL preloaded_url;

[xiyuan, 2016/12/09 22:37:30]

nit: #include "url/gurl.h" and get rid of forward decl since we declare it as
member.

[jdufault, 2016/12/12 18:23:09]

Done.

+  };
+
   // Internal class name.
   static const char kViewClassName[];
 
-  WebUILoginView();
+  explicit WebUILoginView(const WebViewSettings& settings);
   ~WebUILoginView() override;
 
   // Initializes the webui login view.
   virtual void Init();
 
   // Overridden from views::View:
   bool AcceleratorPressed(const ui::Accelerator& accelerator) override;
   const char* GetClassName() const override;
   void RequestFocus() override;
 
@@ skipping 38 matching lines @@
   void set_is_hidden(bool hidden) { is_hidden_ = hidden; }
 
   bool webui_visible() const { return webui_visible_; }
 
   // Let suppress emission of this signal.
   void set_should_emit_login_prompt_visible(bool emit) {
     should_emit_login_prompt_visible_ = emit;
   }
 
  protected:
+  static void InitializeWebView(views::WebView* web_view);

[xiyuan, 2016/12/09 22:37:30]

nit: no need to expose this in header, put it in the anonymous namespace in cc
file

[jdufault, 2016/12/12 18:23:09]

This is needed for preloading the webview (done in a child CL).

+
   // Overridden from views::View:
   void Layout() override;
   void OnLocaleChanged() override;
   void ChildPreferredSizeChanged(View* child) override;
   void AboutToRequestFocusFromTabTraversal(bool reverse) override;
 
   // Overridden from content::NotificationObserver.
   void Observe(int type,
                const content::NotificationSource& source,
                const content::NotificationDetails& details) override;
@@ skipping 23 matching lines @@
                              const blink::WebGestureEvent& event) override;
 
   // Performs series of actions when login prompt is considered
   // to be ready and visible.
   // 1. Emits LoginPromptVisible signal if needed
   // 2. Notifies OOBE/sign classes.
   void OnLoginPromptVisible();
 
   content::NotificationRegistrar registrar_;
 
+  // WebView configuration options.
+  WebViewSettings settings_;

[xiyuan, 2016/12/09 22:37:30]

nit: const WebViewSettings if we don't need to change |settings_|.

[jdufault, 2016/12/12 18:23:09]

Done.

+
+  // True if the current webview instance (ie, GetWebUI()) has been reused.
+  bool is_reusing_webview_ = false;
+
+  // Prevents the webview from being destroyed while it is in use.
+  std::unique_ptr<SharedWebViewUsageHandle> webview_usage_handle_;
+
   // Converts keyboard events on the WebContents to accelerators.
   views::UnhandledKeyboardEventHandler unhandled_keyboard_event_handler_;
 
   // Maps installed accelerators to OOBE webui accelerator identifiers.
   AccelMap accel_map_;
 
   // True when WebUI is being initialized hidden.
   bool is_hidden_ = false;
 
   // True when the WebUI has finished initializing and is visible.
@@ skipping 18 matching lines @@
   std::unique_ptr<CycleFocusTraversable> cycle_focus_traversable_;
 
   base::ObserverList<web_modal::ModalDialogHostObserver> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(WebUILoginView);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_UI_WEBUI_LOGIN_VIEW_H_