Animate the OverviewButtonTray

ash/system/tray/tray_background_view.cc

Index: ash/system/tray/tray_background_view.cc
diff --git a/ash/system/tray/tray_background_view.cc b/ash/system/tray/tray_background_view.cc
index fc24c14932af7c4673e9a46c1d195ce8701d965a..7574664bd5f8c5248a15cbf0c7a720a821d466b2 100644
--- a/ash/system/tray/tray_background_view.cc
+++ b/ash/system/tray/tray_background_view.cc
@@ -22,12 +22,17 @@
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/base/resource/resource_bundle.h"
+#include "ui/compositor/layer.h"
+#include "ui/compositor/layer_animation_element.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_skia.h"
 #include "ui/gfx/image/image_skia_operations.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/screen.h"
 #include "ui/gfx/skia_util.h"
+#include "ui/gfx/transform.h"
 #include "ui/views/background.h"
 #include "ui/views/layout/box_layout.h"
 
@@ -38,6 +43,8 @@ const int kTrayBackgroundHoverAlpha = 150;
 const SkColor kTrayBackgroundPressedColor = SkColorSetRGB(66, 129, 244);
 
 const int kAnimationDurationForPopupMS = 200;
+const int kAnimationDurationForVisibility = 250;

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

Does this need to match the status area widget duration? If so, you should share
a constant.

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

They currently match in the spec. However the spec is due for tweaking once they
can test the implementation. So they are not guaranteed to remain the same.

+const int kShowAnimationDelay = 100;
 
 }  // namespace
 
@@ -307,6 +314,9 @@ TrayBackgroundView::TrayBackgroundView(StatusAreaWidget* status_area_widget)
   tray_container_ = new TrayContainer(shelf_alignment_);
   SetContents(tray_container_);
   tray_event_filter_.reset(new TrayEventFilter);
+
+  SetPaintToLayer(true);
+  SetFillsBoundsOpaquely(false);
 }
 
 TrayBackgroundView::~TrayBackgroundView() {
@@ -319,6 +329,45 @@ void TrayBackgroundView::Initialize() {
   SetTrayBorder();
 }
 
+void TrayBackgroundView::SetVisible(bool visible) {
+  if (visible == this->visible())
+    return;
+
+  if (!this->visible()) {
+    // A translation transform was applied when becoming hidden. However the
+    // alignment of the shelf can change. Reset the offscreen transform so that
+    // the animation to becoming visible reflects the changed layout.
+    HideTransformation();

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

Given visible != this->visible(), if !this->visible() then visible is true,
merge with following if statement.

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

Done.

+  }
+
+  if (visible)
+    views::View::SetVisible(visible);

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

Comment that SetVisible(false) is deferred until after the animation completes
in OnImplicitAnimationsCompleted.

I'm not sure if this will be problematic in terms of visibility calculations
from other classes but I defer to someone else for this.

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

Done.

+
+  layer()->GetAnimator()->StopAnimating();
+  ui::ScopedLayerAnimationSettings animation(layer()->GetAnimator());
+  animation.SetTransitionDuration(base::TimeDelta::FromMilliseconds(
+      kAnimationDurationForVisibility));
+  animation.SetPreemptionStrategy(
+      ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+  animation.AddObserver(this);
+
+  if (visible) {
+    animation.SetTweenType(gfx::Tween::EASE_OUT);
+    layer()->GetAnimator()->SchedulePauseForProperties(

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

Why is the show delayed? Add comment as to why.

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

Done.

+        base::TimeDelta::FromMilliseconds(kShowAnimationDelay),
+        ui::LayerAnimationElement::OPACITY |
+        ui::LayerAnimationElement::TRANSFORM);
+    layer()->SetOpacity(1.0f);
+    gfx::Transform transform;
+    transform.Translate(0.0f, 0.0f);
+    layer()->SetTransform(transform);
+  } else {
+    animation.SetTweenType(gfx::Tween::EASE_IN);
+    layer()->SetOpacity(0.0f);

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

Perhaps also layer()->SetVisible(false);

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

Done.

+    HideTransformation();
+  }
+}
+
 const char* TrayBackgroundView::GetClassName() const {
   return kViewClassName;
 }
@@ -420,6 +469,21 @@ void TrayBackgroundView::SetTrayBorder() {
       top_edge, left_edge, bottom_edge, right_edge));
 }
 
+void TrayBackgroundView::OnImplicitAnimationsCompleted() {
+  if (layer()->opacity() == 0.0f)

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

It might be more robust to compare the layer's visibility to the view's
visibility and change the view if they don't match.

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

Moved the listener to only be added for the !visible case. Since it is the only
one for which we have an action.

+    views::View::SetVisible(false);
+}
+
+void TrayBackgroundView::HideTransformation() {
+  gfx::Transform transform;
+  if (shelf_alignment_ == SHELF_ALIGNMENT_BOTTOM ||
+      shelf_alignment_ == SHELF_ALIGNMENT_TOP)
+    transform.Translate(width(), 0.0f);
+  else
+    transform.Translate(0.0f, height());
+  layer()->SetTransform(transform);
+}
+
 void TrayBackgroundView::InitializeBubbleAnimations(
     views::Widget* bubble_widget) {
   wm::SetWindowVisibilityAnimationType(