Makes the current page dim out when transitioning to instant preview.

chrome/browser/ui/views/frame/contents_container.h

 // Copyright (c) 2010 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_FRAME_CONTENTS_CONTAINER_H_
 #define CHROME_BROWSER_UI_VIEWS_FRAME_CONTENTS_CONTAINER_H_
 #pragma once
 
+#include "app/animation.h"
+#include "base/scoped_ptr.h"
 #include "views/view.h"
 
+class SlideAnimation;
 class TabContents;
 
+namespace views {
+class Widget;
+}
+
 // ContentsContainer is responsible for managing the TabContents views.
 // ContentsContainer has up to two children: one for the currently active
 // TabContents and one for instant's TabContents.
-class ContentsContainer : public views::View {
+class ContentsContainer : public views::View, public AnimationDelegate {
  public:
   explicit ContentsContainer(views::View* active);
   virtual ~ContentsContainer();
 
   // Makes the preview view the active view and nulls out the old active view.
   // It's assumed the caller will delete or remove the old active view
   // separately.
   void MakePreviewContentsActiveContents();
 
   // Sets the preview view. This does not delete the old.
   void SetPreview(views::View* preview, TabContents* preview_tab_contents);
 
   TabContents* preview_tab_contents() const { return preview_tab_contents_; }
 
   // Sets the active top margin.
   void SetActiveTopMargin(int margin);
 
   // Returns the bounds of the preview. If the preview isn't active this
   // retuns the bounds the preview would be shown at.
   gfx::Rect GetPreviewBounds();
 
+  // Fades out the active contents.
+  void FadeActiveContents();
+
+  // Removes the fade. This is done implicitly when the preview is made active.
+  void RemoveFade();
+
   // View overrides:
   virtual void Layout();
 
+  // AnimationDelegate overrides:
+  virtual void AnimationProgressed(const Animation* animation);
+
  private:
   views::View* active_;
 
   views::View* preview_;
 
   TabContents* preview_tab_contents_;
 
+  // Translucent Widget positioned right above the active view that is used to
+  // make the active view appear faded out.
+  views::Widget* active_overlay_;
+
+  // Animation used to vary the opacity of active_overlay.
+  scoped_ptr<SlideAnimation> overlay_animation_;
+
   // The margin between the top and the active view. This is used to make the
   // preview overlap the bookmark bar on the new tab page.
   int active_top_margin_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentsContainer);
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_FRAME_CONTENTS_CONTAINER_H_