Fix the white flicker of the keyboard overlay when it first appearing.

chrome/browser/ui/views/keyboard_overlay_delegate.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_VIEWS_KEYBOARD_OVERLAY_DELEGATE_H_
 #define CHROME_BROWSER_UI_VIEWS_KEYBOARD_OVERLAY_DELEGATE_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "chrome/browser/ui/webui/web_dialog_delegate.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
 
+class KeyboardOverlayDialogView;
 class WebDialogView;
 
-class KeyboardOverlayDelegate : public WebDialogDelegate {
+class KeyboardOverlayDelegate : public WebDialogDelegate,
+                                public content::NotificationObserver {
  public:
   explicit KeyboardOverlayDelegate(const string16& title);
 
-  WebDialogView* view() { return view_; }
-  void set_view(WebDialogView* view) { view_ = view; }
+  // Shows the keyboard overlay.
+  void Show(KeyboardOverlayDialogView* view);
 
   // Overridden from WebDialogDelegate:
   virtual void GetDialogSize(gfx::Size* size) const OVERRIDE;
 
  private:
   virtual ~KeyboardOverlayDelegate();
 
   // Overridden from WebDialogDelegate:
   virtual ui::ModalType GetDialogModalType() const OVERRIDE;
   virtual string16 GetDialogTitle() const OVERRIDE;
   virtual GURL GetDialogContentURL() const OVERRIDE;
   virtual void GetWebUIMessageHandlers(
       std::vector<content::WebUIMessageHandler*>* handlers) const OVERRIDE;
   virtual std::string GetDialogArgs() const OVERRIDE;
+  virtual void OnDialogShown(
+      content::WebUI* webui,
+      content::RenderViewHost* render_view_host) OVERRIDE;
   virtual void OnDialogClosed(const std::string& json_retval) OVERRIDE;
   virtual void OnCloseContents(content::WebContents* source,
                                bool* out_close_dialog) OVERRIDE;
   virtual bool ShouldShowDialogTitle() const OVERRIDE;
   virtual bool HandleContextMenu(
       const content::ContextMenuParams& params) OVERRIDE;
 
+  // Overridden from content::NotificationObserver:
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
   // The dialog title.
   string16 title_;
 
   // The view associated with this delegate.
   // This class does not own the pointer.
   WebDialogView* view_;
 
+  // Whether the associated web contents has been loaded.
+  bool loaded_;
+
+  content::NotificationRegistrar registrar_;
+
   DISALLOW_COPY_AND_ASSIGN(KeyboardOverlayDelegate);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_KEYBOARD_OVERLAY_DELEGATE_H_