Implement initial version of scroll end effect

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

 // Copyright 2013 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_SCROLL_END_EFFECT_CONTROLLER_ASH_H_
 #define CHROME_BROWSER_UI_VIEWS_FRAME_SCROLL_END_EFFECT_CONTROLLER_ASH_H_
 
 #include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
 #include "chrome/browser/ui/views/frame/scroll_end_effect_controller.h"
+#include "ui/compositor/layer.h"
+#include "ui/gfx/animation/animation_delegate.h"
+#include "ui/gfx/animation/slide_animation.h"
+#include "ui/gfx/rect.h"
+#include "ui/gfx/transform.h"
 
-class ScrollEndEffectControllerAsh : public ScrollEndEffectController {
+namespace views {
+class View;
+}
+
+// Class that implements the scroll end effect by controlling the layout of
+// layers and the transforms applied to them. This class depends heavily on
+// ScrollEndEffectControllerDelegate, which is implemented in BrowserView.
+class ScrollEndEffectControllerAsh : public ScrollEndEffectController,
+                                     public gfx::AnimationDelegate {
  public:
-  ScrollEndEffectControllerAsh();
+  explicit ScrollEndEffectControllerAsh(
+      ScrollEndEffectControllerDelegate* delegate);
   virtual ~ScrollEndEffectControllerAsh();
 
-  // ScrollEndEffectController overides:
+  // ScrollEndEffectController overrides:
   virtual void OverscrollUpdate(int delta_y) OVERRIDE;
 
+  // gfx::AnimationDelegate overrides:
+  virtual void AnimationEnded(const gfx::Animation* animation) OVERRIDE;
+  virtual void AnimationProgressed(const gfx::Animation* animation) OVERRIDE;
+
  private:
+  friend class ScrollEndEffectControllerAshTest;
+
+  // Sets up the layer hierarchy for showing the effect. This involves making
+  // sure everything is on a layer and inserting clipping layers into the
+  // hierarchy.
+  void ActivateEffect();
+
+  // Restores the layer hierarchy and states to what they were before the effect
+  // was actived.
+  void DeactivateEffect();
+
+  // Computes the transforms and counter transforms that are needed to produce
+  // the desired effect then applies them. The bounds of the layers may be
+  // adjusted due to a call to SetBoundsForEffect, so need to be stored before
+  // calling. The entire window is scaled and possibly translated to produce the
+  // squishing effect. The non-client area and the content are counter scaled to
+  // preserve their size and translated/clipped to fit in the smaller window.
+  void ApplyDelta(int delta_y);
+
+  ScrollEndEffectControllerDelegate* delegate_;  // non-owned
+  bool is_effect_active_;
+
+  // The size of the frame at the size of the effect, so that the effect can

[sadrul, 2013/10/25 18:28:25]

'at the beginning/start of the effect'?

[rharrison, 2013/11/18 21:52:26]

Done.

+  // scale relative to that and it can be restored at the end.
+  gfx::Rect frame_bounds_;
+
+  // Control variables related to the current delta_y being applied for the
+  // effect and used when animating.
+  int start_delta_y_;
+  int current_delta_y_;
+  int end_delta_y_;
+
+  scoped_ptr<gfx::SlideAnimation> animation_;
+
   DISALLOW_COPY_AND_ASSIGN(ScrollEndEffectControllerAsh);
  };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_FRAME_SCROLL_END_EFFECT_CONTROLLER_ASH_H_