alternate ntp: toolbar background and separator animation

chrome/browser/ui/search/toolbar_search_animator.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_SEARCH_TOOLBAR_SEARCH_ANIMATOR_H_
 #define CHROME_BROWSER_UI_SEARCH_TOOLBAR_SEARCH_ANIMATOR_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
-#include "base/timer.h"
 #include "chrome/browser/ui/search/search_model_observer.h"
+#include "chrome/browser/ui/search/search_types.h"
 #include "ui/base/animation/animation_delegate.h"
 
 class TabContents;
 
 namespace ui {
-class SlideAnimation;
+class MultiAnimation;
 }
 
 namespace chrome {
 namespace search {
 
 class SearchModel;
 class ToolbarSearchAnimatorObserver;
 
-// ToolbarSearchAnimator is used to track the background state of the toolbar
-// and related classes.  To use ToolbarSearchAnimator, add a
+// ToolbarSearchAnimator is used to track the gradient background state of the
+// toolbar and related classes.  To use ToolbarSearchAnimator, add a
 // ToolbarSearchAnimatorObserver.  The ToolbarSearchAnimatorObserver is then
 // notified appropriately.
 class ToolbarSearchAnimator : public SearchModelObserver,
                               public ui::AnimationDelegate {
  public:
-  // State of background to paint by observers, only applicable for
-  // |MODE_SEARCH|.
-  enum BackgroundState {
-    // Background state is not applicable.
-    BACKGROUND_STATE_DEFAULT = 0,
-    // Show background for |MODE_NTP|.
-    BACKGROUND_STATE_NTP = 0x01,
-    // Show background for |MODE_SEARCH|.
-    BACKGROUND_STATE_SEARCH = 0x02,
-    // Show backgrounds for both |MODE_NTP| and |MODE_SEARCH|.
-    BACKGROUND_STATE_NTP_SEARCH = BACKGROUND_STATE_NTP |
-                                  BACKGROUND_STATE_SEARCH,
-  };
-
   explicit ToolbarSearchAnimator(SearchModel* search_model);
   virtual ~ToolbarSearchAnimator();
 
-  // Get the current background state to paint.
-  // |search_background_opacity| contains a valid opacity value only if
-  // background for |MODE_SEARCH| needs to be shown i.e. |background_state| is
-  // BACKGROUND_STATE_SEARCH or BACKGROUND_STATE_NTP_SEARCH.
-  // Only call this for |MODE_SEARCH|.
-  void GetCurrentBackgroundState(BackgroundState* background_state,
-                                 double* search_background_opacity) const;
+  // Get the gradient background opacity to paint for toolbar and active tab, a
+  // value between 0f and 1f inclusive:
+  // - 0f: only paint flat background
+  // - < 1f: paint flat background at full opacity and gradient background at
+  //   specified opacity
+  // - 1f: only paint gradient background at full opacity
+  double GetGradientOpacity() const;
 
   // Called from SearchDelegate::StopObservingTab() when a tab is deactivated or
   // closing or detached, to jump to the end state of the animation.
   // This allows a reactivated tab to show the end state of the animation,
   // rather than the transient state.
   void FinishAnimation(TabContents* tab_contents);
 
   // Add and remove observers.
   void AddObserver(ToolbarSearchAnimatorObserver* observer);
   void RemoveObserver(ToolbarSearchAnimatorObserver* observer);
 
   // Overridden from SearchModelObserver:
-  virtual void ModeChanged(const Mode& mode) OVERRIDE;
+  virtual void ModeChanged(const Mode& old_mode, const Mode& new_mode) OVERRIDE;
 
   // Overridden from ui::AnimationDelegate:
   virtual void AnimationProgressed(const ui::Animation* animation) OVERRIDE;
   virtual void AnimationEnded(const ui::Animation* animation) OVERRIDE;
 
  private:
-  // State of animation.
-  enum AnimateState {
-    ANIMATE_STATE_NONE,     // Doing nothing.
-    ANIMATE_STATE_WAITING,  // Waiting to run background animation.
-    ANIMATE_STATE_RUNNING,  // Running background animation.
-  };
+  friend class ToolbarSearchAnimatorTest;
+  friend class ToolbarSearchAnimatorTestObserver;
 
-  // Callback for |background_change_timer_| to actually start the background
-  // change animation.
+  // Helper function to initialize background animation with its parts.
+  void InitBackgroundAnimation(int background_change_delay_ms,
+                               int background_change_duration_ms);
+
+  // Helper function to start animation for gradient background change.
   void StartBackgroundChange();
 
-  // Reset state of animator: reset animate_state_, stop timer or animation,
-  // If we're waiting to animate or animating, i.e. |animate_state| is not
-  // ANIMATE_STAET_NONE, wwe'll notify observers via
-  // ToolbarSearchAnimatorObserver::BackgroundChangeCanceled.
+  // Reset animations by stopping them.
+  // If we're animating background or separator, we'll notify observers via
+  // ToolbarSearchAnimatorObserver::OnToolbarBackgroundAnimatorCanceled or
+  // ToolbarSearchAnimatorObserver::OnToolbarSeparatorAnimatorCanceled
+  // respectively.
   // Pass in |tab_contents| if animation is canceled because of deactivating or
   // detaching or closing a tab.
   void Reset(TabContents* tab_contents);
 
   // Weak.  Owned by Browser.  Non-NULL.
   SearchModel* search_model_;
 
-  // State of animation.
-  AnimateState animate_state_;
-
-  // The background fade animation.
-  scoped_ptr<ui::SlideAnimation> background_animation_;
-
-  // The timer to delay start of animation after mode changes from |MODE_NTP| to
-  // |MODE_SEARCH|.
-  base::OneShotTimer<ToolbarSearchAnimator> background_change_timer_;
+  // The background change animation.
+  scoped_ptr<ui::MultiAnimation> background_animation_;
 
   // Observers.
   ObserverList<ToolbarSearchAnimatorObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(ToolbarSearchAnimator);
 };
 
 }  // namespace chrome
 }  // namespace search
 
 #endif  // CHROME_BROWSER_UI_SEARCH_TOOLBAR_SEARCH_ANIMATOR_H_