Refactor the home card structure and introduce animation.

athena/home/athena_start_page_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 ATHENA_HOME_ATHENA_START_PAGE_VIEW_H_
 #define ATHENA_HOME_ATHENA_START_PAGE_VIEW_H_
 
 #include "base/memory/weak_ptr.h"
 #include "ui/app_list/views/search_box_view_delegate.h"
 #include "ui/views/view.h"
 
 namespace app_list {
 class AppListViewDelegate;
 class SearchBoxView;
 class SearchResultListView;
 }
 
 namespace athena {
 
-// It will replace app_list::StartPageView in Athena UI in the future.
-// Right now it's simply used for VISIBLE_BOTTOM state.
 class AthenaStartPageView : public views::View,
                             public app_list::SearchBoxViewDelegate {
  public:
   explicit AthenaStartPageView(app_list::AppListViewDelegate* delegate);
   virtual ~AthenaStartPageView();
 
   // Requests the focus on the search box in the start page view.
   void RequestFocusOnSearchBox();
 
+  // Updates the layout state. See the comment of |layout_state_| field.
+  void SetLayoutState(float layout_state);
+
+  // Updates the layout state and move the subviews to the target location with
+  // animation.
+  void SetLayoutStateWithAnimation(float layout_state);
+
  private:
+  static const char kViewClassName[];
+
+  // A struct which bundles the layout data of subviews.
+  struct LayoutData {
+    gfx::Rect search_box;
+    gfx::Rect icons;
+    gfx::Rect controls;
+    float logo_opacity;
+    float background_opacity;
+
+    LayoutData();
+  };
+
+  // Returns the bounds for |VISIBLE_BOTTOM|.
+  LayoutData CreateBottomBounds(int width);
+
+  // Returns the bounds for |VISIBLE_CENTERED|.
+  LayoutData CreateCenteredBounds(int width);
+
   // Schedules the animation for the layout the search box and the search
   // results.
   void LayoutSearchResults(bool should_show_search_results);
 
   // Called when the animation of search box / search results layout has
   // completed.
   void OnSearchResultLayoutAnimationCompleted(bool should_show_search_results);
 
   // views::View:
   virtual void Layout() OVERRIDE;
   virtual bool OnKeyPressed(const ui::KeyEvent& key_event) OVERRIDE;
 
   // app_list::SearchBoxViewDelegate:
   virtual void QueryChanged(app_list::SearchBoxView* sender) OVERRIDE;
 
   // Not owned.
   app_list::AppListViewDelegate* delegate_;
 
   // Views are owned through its hierarchy.
   views::View* app_icon_container_;
   views::View* search_box_container_;
   views::View* control_icon_container_;
   views::View* logo_;
   app_list::SearchBoxView* search_box_view_;
   app_list::SearchResultListView* search_results_view_;
 
+  // Do not use views::Background but a views::View with ui::Layer for gradient
+  // background opacity update and animation.
+  views::View* background_;
+
   // The expected height of |search_results_view_|
   int search_results_height_;
 
+  // The state to specify how each of the subviews should be laid out, in the
+  // range of [0, 1]. 0 means fully BOTTOM state, and 1 is fully CENTERED state.
+  float layout_state_;
+
   base::WeakPtrFactory<AthenaStartPageView> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(AthenaStartPageView);
 };
 
 }  // namespace athena
 
 #endif  // ATHENA_HOME_ATHENA_START_PAGE_VIEW_H_