Animate the OverviewButtonTray

ash/system/status_area_widget_delegate.cc

Index: ash/system/status_area_widget_delegate.cc
diff --git a/ash/system/status_area_widget_delegate.cc b/ash/system/status_area_widget_delegate.cc
index babe66d1474ae7f9fc5d9d0e4d15dfec3e0cf756..229023103f00d5493438e3e5d4dccab67a2aec98 100644
--- a/ash/system/status_area_widget_delegate.cc
+++ b/ash/system/status_area_widget_delegate.cc
@@ -10,15 +10,25 @@
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/system/tray/tray_constants.h"
+#include "base/memory/scoped_ptr.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/base/resource/resource_bundle.h"
+#include "ui/compositor/layer.h"
+#include "ui/compositor/scoped_layer_animation_settings.h"
+#include "ui/gfx/animation/tween.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/image/image.h"
 #include "ui/views/accessible_pane_view.h"
 #include "ui/views/layout/grid_layout.h"
 #include "ui/views/widget/widget.h"
 
+namespace {
+
+const int kAnimationDuration = 250;
+
+}  // namespace
+
 namespace ash {
 
 StatusAreaWidgetDelegate::StatusAreaWidgetDelegate()
@@ -27,6 +37,7 @@ StatusAreaWidgetDelegate::StatusAreaWidgetDelegate()
   // Allow the launcher to surrender the focus to another window upon
   // navigation completion by the user.
   set_allow_deactivate_on_esc(true);
+  SetPaintToLayer(true);
 }
 
 StatusAreaWidgetDelegate::~StatusAreaWidgetDelegate() {
@@ -117,12 +128,20 @@ void StatusAreaWidgetDelegate::UpdateLayout() {
       layout->AddView(child);
     }
   }
+
+  layer()->GetAnimator()->StopAnimating();
+  scoped_ptr<ui::ScopedLayerAnimationSettings> animation;
+  animation.reset(SetupAnimationForLayer(layer()));
+
   Layout();
   UpdateWidgetSize();
 }
 
 void StatusAreaWidgetDelegate::ChildPreferredSizeChanged(View* child) {
   // Need to resize the window when trays or items are added/removed.
+  scoped_ptr<ui::ScopedLayerAnimationSettings> animation;
+  animation.reset(SetupAnimationForLayer(layer()));
+
   UpdateWidgetSize();
 }
 
@@ -135,4 +154,18 @@ void StatusAreaWidgetDelegate::UpdateWidgetSize() {
     GetWidget()->SetSize(GetPreferredSize());
 }
 
+ui::ScopedLayerAnimationSettings*
+    StatusAreaWidgetDelegate::SetupAnimationForLayer(ui::Layer* layer) {

[flackr, 2014/05/06 15:42:11]

Use anonymous namespace, though it'd probably be better to subclass
ScopedLayerAnimationSettings to override these.

[jonross, 2014/05/07 13:52:36]

Done.

+  if (!layer)
+    return NULL;
+  ui::ScopedLayerAnimationSettings* settings =
+      new ui::ScopedLayerAnimationSettings(layer->GetAnimator());
+  settings->SetTransitionDuration(
+      base::TimeDelta::FromMilliseconds(kAnimationDuration));
+  settings->SetPreemptionStrategy(
+      ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+  settings->SetTweenType(gfx::Tween::EASE_IN_OUT);
+  return settings;
+}
+
 }  // namespace ash