Animate the OverviewButtonTray

ash/system/status_area_widget_delegate.cc

 // 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.
 
 #include "ash/system/status_area_widget_delegate.h"
 
 #include "ash/ash_export.h"
 #include "ash/ash_switches.h"
 #include "ash/focus_cycler.h"
 #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()
     : focus_cycler_for_testing_(NULL),
       alignment_(SHELF_ALIGNMENT_BOTTOM) {
   // 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() {
 }
 
 void StatusAreaWidgetDelegate::SetFocusCyclerForTesting(
     const FocusCycler* focus_cycler) {
   focus_cycler_for_testing_ = focus_cycler;
 }
 
@@ skipping 70 matching lines @@
       views::View* child = child_at(c);
       if (!child->visible())
         continue;
       if (!is_first_visible_child)
         layout->AddPaddingRow(0, kTraySpacing);
       is_first_visible_child = false;
       layout->StartRow(0, 0);
       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();
 }
 
 void StatusAreaWidgetDelegate::ChildVisibilityChanged(View* child) {
   UpdateLayout();
 }
 
 void StatusAreaWidgetDelegate::UpdateWidgetSize() {
   if (GetWidget())
     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