Introduce the basic animation from minimized to bottom.

athena/home/home_card_impl.cc

Index: athena/home/home_card_impl.cc
diff --git a/athena/home/home_card_impl.cc b/athena/home/home_card_impl.cc
index 9c993f2c413a80fe3a3dc3d3450a5ce932381b02..99e2169e8412b7bc678ef23d8e55a9cf5c8f7376 100644
--- a/athena/home/home_card_impl.cc
+++ b/athena/home/home_card_impl.cc
@@ -22,6 +22,8 @@
 #include "ui/app_list/views/contents_view.h"
 #include "ui/aura/layout_manager.h"
 #include "ui/aura/window.h"
+#include "ui/compositor/layer_animation_observer.h"
+#include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/views/background.h"
 #include "ui/views/layout/box_layout.h"
 #include "ui/views/widget/widget.h"
@@ -88,8 +90,13 @@ class HomeCardLayoutManager : public aura::LayoutManager {
     if (!home_card || !home_card->GetRootWindow())
       return;
 
-    SetChildBoundsDirect(home_card, GetBoundsForState(
-        home_card->GetRootWindow()->bounds(), delegate_->GetState()));
+    {
+      ui::ScopedLayerAnimationSettings settings(
+          home_card->layer()->GetAnimator());
+      settings.SetTweenType(gfx::Tween::EASE_IN_OUT);
+      SetChildBoundsDirect(home_card, GetBoundsForState(
+          home_card->GetRootWindow()->bounds(), delegate_->GetState()));
+    }
   }
 
  private:
@@ -323,6 +330,29 @@ class HomeCardView : public views::WidgetDelegateView {
                       wm::SHADOW_TYPE_RECTANGULAR);
   }
 
+  void SetStateWithAnimation(HomeCard::State from_state,
+                             HomeCard::State to_state) {
+    if ((from_state == HomeCard::VISIBLE_MINIMIZED &&
+         to_state == HomeCard::VISIBLE_BOTTOM) ||
+        (from_state == HomeCard::VISIBLE_BOTTOM &&
+         to_state == HomeCard::VISIBLE_MINIMIZED)) {
+      minimized_view_->SetVisible(true);
+      bottom_view_->SetVisible(true);
+      {
+        ui::ScopedLayerAnimationSettings settings(
+            minimized_view_->layer()->GetAnimator());
+        settings.SetTweenType(gfx::Tween::EASE_IN_OUT);
+        settings.SetTransitionDuration(base::TimeDelta::FromSeconds(5));

[sadrul, 2014/08/15 15:36:21]

That's ... pretty long! Was for debugging, perhaps?

[Jun Mukai, 2014/08/15 16:35:07]

Ugh, removed. That is for debugging. Thanks for catching.

+        settings.AddObserver(new AnimationObserver(this, to_state));
+        minimized_view_->layer()->SetOpacity(
+            (to_state == HomeCard::VISIBLE_MINIMIZED) ? 1.0f : 0.0f);

[sadrul, 2014/08/15 15:36:21]

Do you need to set the opacity to 0/1 beforehand to make sure it does animate?

[Jun Mukai, 2014/08/15 16:35:08]

Not sure what you mean, but if you meant the pattern of: SetOpacity(0); {
ScopedLayerAnimationSettings; ...; SetOpacity(1); }, I don't think we should.

In case of touch swipe, minimized view is in intermediate opacity (see line 309
above), and the animation should start from the current opacity.

[sadrul, 2014/08/15 16:37:26]

Sounds good.

+      }
+    } else {
+      // TODO(mukai): Take care of other transition.
+      SetState(to_state);
+    }
+  }
+
   void ClearGesture() {
     gesture_manager_.reset();
   }
@@ -356,6 +386,26 @@ class HomeCardView : public views::WidgetDelegateView {
   }
 
  private:
+  class AnimationObserver : public ui::ImplicitAnimationObserver {

[sadrul, 2014/08/15 15:36:22]

You should use ui::ClosureAnimationObserver!

[Jun Mukai, 2014/08/15 16:35:08]

Done!

+   public:
+    AnimationObserver(HomeCardView* view, HomeCard::State target_state)
+        : view_(view),
+          target_state_(target_state) {}
+    virtual ~AnimationObserver() {}
+
+   private:
+    // ui::ImplicitAnimationObserver:
+    virtual void OnImplicitAnimationsCompleted() OVERRIDE {
+      view_->SetState(target_state_);
+      delete this;
+    }
+
+    HomeCardView* view_;
+    HomeCard::State target_state_;
+
+    DISALLOW_COPY_AND_ASSIGN(AnimationObserver);
+  };
+
   virtual views::View* GetContentsView() OVERRIDE {
     return this;
   }
@@ -506,6 +556,7 @@ void HomeCardImpl::SetState(HomeCard::State state) {
 
   // Update |state_| before changing the visibility of the widgets, so that
   // LayoutManager callbacks get the correct state.
+  HomeCard::State old_state = state_;
   state_ = state;
   original_state_ = state;
   if (state_ == HIDDEN) {
@@ -515,7 +566,7 @@ void HomeCardImpl::SetState(HomeCard::State state) {
       home_card_widget_->Show();
     else
       home_card_widget_->ShowInactive();
-    home_card_view_->SetState(state);
+    home_card_view_->SetStateWithAnimation(old_state, state);
     layout_manager_->Layout();
   }
 }
@@ -568,8 +619,9 @@ void HomeCardImpl::OnGestureEnded(State final_state) {
       (state_ == VISIBLE_MINIMIZED || final_state == VISIBLE_MINIMIZED)) {
     WindowManager::GetInstance()->ToggleOverview();
   } else {
+    HomeCard::State old_state = state_;
     state_ = final_state;
-    home_card_view_->SetState(final_state);
+    home_card_view_->SetStateWithAnimation(old_state, final_state);
     layout_manager_->Layout();
   }
 }