Replaced BackgroundAnimator with ShelfBackgroundAnimator.

ash/shelf/shelf_widget.cc

Index: ash/shelf/shelf_widget.cc
diff --git a/ash/shelf/shelf_widget.cc b/ash/shelf/shelf_widget.cc
index 9c6ea09e47ceb3b30eb83bbfe3b3e5b31d49cc67..b89ab13880a524e8edccf693a1705b06e47607e4 100644
--- a/ash/shelf/shelf_widget.cc
+++ b/ash/shelf/shelf_widget.cc
@@ -9,6 +9,7 @@
 #include "ash/aura/wm_window_aura.h"
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/session/session_state_delegate.h"
+#include "ash/common/shelf/shelf_background_animator_observer.h"
 #include "ash/common/shelf/shelf_constants.h"
 #include "ash/common/shelf/shelf_model.h"
 #include "ash/common/shelf/wm_shelf_util.h"
@@ -80,11 +81,14 @@ class DimmerView : public views::View,
   const views::Widget* GetWidget() const override { return View::GetWidget(); }
 
   // BackgroundAnimatorDelegate overrides:
-  void UpdateBackground(int alpha) override {
+  void UpdateBackground(BackgroundAnimator* animator, int alpha) override {
     alpha_ = alpha;
     SchedulePaint();
   }
 
+  void BackgroundAnimationEnded(BackgroundAnimator* animator,
+                                bool successful) override {}
+
   // views::View overrides:
   void OnPaintBackground(gfx::Canvas* canvas) override;
 
@@ -302,8 +306,8 @@ class ShelfWindowTargeter : public ::wm::EasyResizeWindowTargeter,
 // sizes it to the width of the shelf minus the size of the status area.
 class ShelfWidget::DelegateView : public views::WidgetDelegate,
                                   public views::AccessiblePaneView,
-                                  public BackgroundAnimatorDelegate,
-                                  public aura::WindowObserver {
+                                  public aura::WindowObserver,
+                                  public ShelfBackgroundAnimatorObserver {
  public:
   explicit DelegateView(ShelfWidget* shelf);
   ~DelegateView() override;
@@ -343,8 +347,9 @@ class ShelfWidget::DelegateView : public views::WidgetDelegate,
                              const gfx::Rect& old_bounds,
                              const gfx::Rect& new_bounds) override;
 
-  // BackgroundAnimatorDelegate overrides:
-  void UpdateBackground(int alpha) override;
+  // ShelfBackgroundAnimatorObserver:
+  void UpdateShelfOpaqueBackground(int alpha) override;
+  void UpdateShelfAssetBackground(int alpha) override;
 
   // Force the shelf to be presented in an undimmed state.
   void ForceUndimming(bool force);
@@ -367,7 +372,8 @@ class ShelfWidget::DelegateView : public views::WidgetDelegate,
   ShelfWidget* shelf_;
   std::unique_ptr<views::Widget> dimmer_;
   FocusCycler* focus_cycler_;
-  int alpha_;
+  int asset_background_alpha_;

[James Cook, 2016/06/14 17:50:02]

Hooray for more explicit variable names!

+  // TODO(bruthig): Remove opaque_background_.

[James Cook, 2016/06/14 17:50:02]

Please file a bug for this and reference it here.

[bruthig, 2016/07/26 19:50:03]

Done.

   // A black background layer which is shown when a maximized window is visible.
   ui::Layer opaque_background_;
   // A black foreground layer which is shown while transitioning between users.
@@ -387,7 +393,7 @@ class ShelfWidget::DelegateView : public views::WidgetDelegate,
 ShelfWidget::DelegateView::DelegateView(ShelfWidget* shelf)
     : shelf_(shelf),
       focus_cycler_(NULL),
-      alpha_(0),
+      asset_background_alpha_(0),
       opaque_background_(ui::LAYER_SOLID_COLOR),
       opaque_foreground_(ui::LAYER_SOLID_COLOR),
       dimmer_view_(NULL),
@@ -450,9 +456,7 @@ void ShelfWidget::DelegateView::SetParentLayer(ui::Layer* layer) {
 }
 
 void ShelfWidget::DelegateView::OnPaintBackground(gfx::Canvas* canvas) {
-  if (MaterialDesignController::IsShelfMaterial()) {
-    canvas->FillRect(bounds(), SkColorSetA(kShelfBaseColor, alpha_));
-  } else {
+  if (!MaterialDesignController::IsShelfMaterial()) {
     ui::ResourceBundle* rb = &ui::ResourceBundle::GetSharedInstance();
     gfx::ImageSkia shelf_background =
         *rb->GetImageSkiaNamed(IDR_ASH_SHELF_BACKGROUND);
@@ -465,7 +469,7 @@ void ShelfWidget::DelegateView::OnPaintBackground(gfx::Canvas* canvas) {
     }
     const gfx::Rect dock_bounds(shelf_->shelf_layout_manager()->dock_bounds());
     SkPaint paint;
-    paint.setAlpha(alpha_);
+    paint.setAlpha(asset_background_alpha_);
     canvas->DrawImageInt(
         shelf_background, 0, 0, shelf_background.width(),
         shelf_background.height(),
@@ -560,8 +564,13 @@ gfx::Rect ShelfWidget::DelegateView::GetDimmerBoundsForTest() {
   return gfx::Rect();
 }
 
-void ShelfWidget::DelegateView::UpdateBackground(int alpha) {
-  alpha_ = alpha;
+void ShelfWidget::DelegateView::UpdateShelfOpaqueBackground(int alpha) {
+  const double kMaxAlpha = 255.0;

[James Cook, 2016/06/14 17:50:02]

could be a float

[bruthig, 2016/07/26 19:50:03]

Done.

+  opaque_background_.SetOpacity(alpha / kMaxAlpha);
+}
+
+void ShelfWidget::DelegateView::UpdateShelfAssetBackground(int alpha) {
+  asset_background_alpha_ = alpha;
   SchedulePaint();
 }
 
@@ -569,8 +578,6 @@ ShelfWidget::ShelfWidget(WmWindow* wm_shelf_container,
                          WmWindow* wm_status_container,
                          WorkspaceController* workspace_controller)
     : delegate_view_(new DelegateView(this)),
-      background_animator_(
-          delegate_view_, 0, GetShelfConstant(SHELF_BACKGROUND_ALPHA)),
       activating_as_fallback_(false) {
   views::Widget::InitParams params(
       views::Widget::InitParams::TYPE_WINDOW_FRAMELESS);
@@ -595,6 +602,8 @@ ShelfWidget::ShelfWidget(WmWindow* wm_shelf_container,
   shelf_layout_manager_->set_workspace_controller(workspace_controller);
   workspace_controller->SetShelf(shelf_layout_manager_);
 
+  background_animator_.AddObserver(delegate_view_);

[James Cook, 2016/06/14 17:50:02]

Does this need to be done here, or could it happen around line 582, nearer to
where delegate_view_ is constructed?

Where is this observer removed?

[bruthig, 2016/07/26 19:50:03]

Done.

+
   status_area_widget_ = new StatusAreaWidget(wm_status_container, this);
   status_area_widget_->CreateTrayViews();
   if (Shell::GetInstance()->session_state_delegate()->
@@ -602,6 +611,7 @@ ShelfWidget::ShelfWidget(WmWindow* wm_shelf_container,
     status_area_widget_->Show();
   }
   Shell::GetInstance()->focus_cycler()->AddWidget(status_area_widget_);
+  background_animator_.AddObserver(status_area_widget_);
 
   aura::Window* status_container =
       WmWindowAura::GetAuraWindow(wm_status_container);
@@ -613,6 +623,11 @@ ShelfWidget::ShelfWidget(WmWindow* wm_shelf_container,
   status_container->SetEventTargeter(std::unique_ptr<ui::EventTargeter>(
       new ShelfWindowTargeter(status_container, shelf_layout_manager_)));
 
+  // Forcefully paint the background after all observers have been added so they
+  // paint properly the first time.
+  background_animator_.PaintBackground(SHELF_BACKGROUND_DEFAULT,
+                                       BACKGROUND_CHANGE_IMMEDIATE);
+
   views::Widget::AddObserver(this);
 }
 
@@ -627,32 +642,11 @@ ShelfWidget::~ShelfWidget() {
 void ShelfWidget::SetPaintsBackground(
     ShelfBackgroundType background_type,
     BackgroundAnimatorChangeType change_type) {
-  ui::Layer* opaque_background = delegate_view_->opaque_background();
-  float target_opacity =
-      (background_type == SHELF_BACKGROUND_MAXIMIZED) ? 1.0f : 0.0f;
-  std::unique_ptr<ui::ScopedLayerAnimationSettings> opaque_background_animation;
-  if (change_type != BACKGROUND_CHANGE_IMMEDIATE) {
-    opaque_background_animation.reset(new ui::ScopedLayerAnimationSettings(
-        opaque_background->GetAnimator()));
-    opaque_background_animation->SetTransitionDuration(
-        base::TimeDelta::FromMilliseconds(kTimeToSwitchBackgroundMs));
-  }
-  opaque_background->SetOpacity(target_opacity);
-
-  // TODO(mukai): use ui::Layer on both opaque_background and normal background
-  // retire background_animator_ at all. It would be simpler.
-  // See also DockedBackgroundWidget::SetPaintsBackground.
-  background_animator_.SetPaintsBackground(
-      background_type != SHELF_BACKGROUND_DEFAULT, change_type);
+  background_animator_.PaintBackground(background_type, change_type);
 }
 
 ShelfBackgroundType ShelfWidget::GetBackgroundType() const {
-  if (delegate_view_->opaque_background()->GetTargetOpacity() == 1.0f)
-    return SHELF_BACKGROUND_MAXIMIZED;
-  if (background_animator_.paints_background())
-    return SHELF_BACKGROUND_OVERLAP;
-
-  return SHELF_BACKGROUND_DEFAULT;
+  return background_animator_.target_background_type();
 }
 
 void ShelfWidget::HideShelfBehindBlackBar(bool hide, int animation_time_ms) {
@@ -735,6 +729,10 @@ void ShelfWidget::CreateShelf(WmShelfAura* wm_shelf_aura) {
   // Must be initialized before the delegate is notified because the delegate
   // may try to access the WmShelf.
   wm_shelf_aura->SetShelf(shelf_.get());
+  // TODO(bruthig): Is this the best/right place to attach the
+  // |background_animator_|? Does |background_animator_| need to be removed as
+  // an observer?
+  wm_shelf_aura->AddObserver(&background_animator_);

[James Cook, 2016/06/14 17:50:02]

Given that the items being animated are built in the ShelfWidget constructor,
maybe the observer should be added there?

If so, you could pass in WmShelf there. WmShelf exists for the lifetime of the
RootWindowController.

Also, I think the observer should be removed.

[bruthig, 2016/07/26 19:50:03]

Done.

   delegate->OnShelfCreated(shelf_.get());
 
   SetFocusCycler(shell->focus_cycler());
@@ -778,6 +776,7 @@ void ShelfWidget::Shutdown() {
 
   if (status_area_widget_) {
     Shell::GetInstance()->focus_cycler()->RemoveWidget(status_area_widget_);
+    background_animator_.RemoveObserver(status_area_widget_);
     status_area_widget_->Shutdown();
     status_area_widget_ = nullptr;
   }