[ash-md] Animates overview shield in and out

ash/common/wm/overview/window_grid.cc

Index: ash/common/wm/overview/window_grid.cc
diff --git a/ash/common/wm/overview/window_grid.cc b/ash/common/wm/overview/window_grid.cc
index 10003074a2dd524a2c284f7ff9437a0cccf6b66e..de555e34b91ef6d229788259f663a57e86ab7c4d 100644
--- a/ash/common/wm/overview/window_grid.cc
+++ b/ash/common/wm/overview/window_grid.cc
@@ -12,6 +12,8 @@
 
 #include "ash/common/ash_switches.h"
 #include "ash/common/material_design/material_design_controller.h"
+#include "ash/common/shelf/shelf_types.h"
+#include "ash/common/shelf/wm_shelf.h"
 #include "ash/common/shell_window_ids.h"
 #include "ash/common/wm/overview/scoped_overview_animation_settings.h"
 #include "ash/common/wm/overview/scoped_overview_animation_settings_factory.h"
@@ -99,7 +101,8 @@ const int kMinCardsMajor = 3;
 const int kOverviewSelectorTransitionMilliseconds = 250;
 
 // The color and opacity of the screen shield in overview.
-const SkColor kShieldColor = SkColorSetARGB(178, 0, 0, 0);
+const SkColor kShieldColor = SkColorSetARGB(255, 0, 0, 0);
+const float kShieldOpacity = 0.7f;
 
 // The color and opacity of the overview selector.
 const SkColor kWindowSelectionColor = SkColorSetARGB(128, 0, 0, 0);
@@ -353,11 +356,13 @@ void ReorderItemsGreedyLeastMovement(std::vector<WmWindow*>* items,
 // |root_window|'s default container and having |background_color|.
 // When |border_thickness| is non-zero, a border is created having
 // |border_color|, otherwise |border_color| parameter is ignored.
+// The new background widget starts with |initial_opacity| and then fades in.
 views::Widget* CreateBackgroundWidget(WmWindow* root_window,
                                       SkColor background_color,
                                       int border_thickness,
                                       int border_radius,
-                                      SkColor border_color) {
+                                      SkColor border_color,
+                                      float initial_opacity) {
   views::Widget* widget = new views::Widget;
   views::Widget::InitParams params;
   params.type = views::Widget::InitParams::TYPE_POPUP;
@@ -395,8 +400,7 @@ views::Widget* CreateBackgroundWidget(WmWindow* root_window,
   widget->SetContentsView(content_view);
   widget_window->GetParent()->StackChildAtTop(widget_window);
   widget->Show();
-  // New background widget starts with 0 opacity and then fades in.
-  widget_window->SetOpacity(0.f);
+  widget_window->SetOpacity(initial_opacity);
   return widget;
 }
 
@@ -433,6 +437,24 @@ WindowGrid::WindowGrid(WmWindow* root_window,
 WindowGrid::~WindowGrid() {
   for (WmWindow* window : observed_windows_)
     window->RemoveObserver(this);
+
+  // Fade out the shield widget. This animation continues past the lifetime
+  // of |this|.
+  WmWindow* widget_window =
+      WmLookup::Get()->GetWindowForWidget(shield_widget_.get());
+  ui::ScopedLayerAnimationSettings animation_settings(
+      widget_window->GetLayer()->GetAnimator());
+  animation_settings.SetTransitionDuration(base::TimeDelta::FromMilliseconds(
+      kOverviewSelectorTransitionMilliseconds));
+  animation_settings.SetTweenType(gfx::Tween::EASE_IN);
+  animation_settings.SetPreemptionStrategy(
+      ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
+  // CleanupWidgetAfterAnimationObserver will delete itself (and the
+  // shield widget) when the opacity animation is complete.
+  views::Widget* shield_widget = shield_widget_.get();
+  animation_settings.AddObserver(
+      new CleanupWidgetAfterAnimationObserver(std::move(shield_widget_)));
+  shield_widget->SetOpacity(0.f);
 }
 
 void WindowGrid::PrepareForOverview() {
@@ -792,8 +814,14 @@ void WindowGrid::OnWindowBoundsChanged(WmWindow* window,
 }
 
 void WindowGrid::InitShieldWidget() {
-  shield_widget_.reset(CreateBackgroundWidget(root_window_, kShieldColor, 0, 0,
-                                              SK_ColorTRANSPARENT));
+  const float initial_opacity =
+      (root_window_->GetRootWindowController()
+           ->GetShelf()
+           ->GetBackgroundType() == SHELF_BACKGROUND_MAXIMIZED)

[bruthig, 2016/07/12 20:43:37]

nit: This is currently based on some assumptions in the shelf implementation,
e.g. the shelf is black in MAXIMIZED mode.  This assumption will change when we
colour the shelf based on the wallpaper.  I think we can defer a solution that
uses the same source colour until later but I think this warrants a TODO
breadcrumb somewhere in this file.

[varkha, 2016/07/12 20:50:09]

Done.

+          ? 1.f
+          : 0.f;
+  shield_widget_.reset(CreateBackgroundWidget(
+      root_window_, kShieldColor, 0, 0, SK_ColorTRANSPARENT, initial_opacity));
 
   WmWindow* widget_window =
       WmLookup::Get()->GetWindowForWidget(shield_widget_.get());
@@ -807,7 +835,7 @@ void WindowGrid::InitShieldWidget() {
   animation_settings.SetTweenType(gfx::Tween::LINEAR_OUT_SLOW_IN);
   animation_settings.SetPreemptionStrategy(
       ui::LayerAnimator::IMMEDIATELY_ANIMATE_TO_NEW_TARGET);
-  shield_widget_->SetOpacity(1.f);
+  shield_widget_->SetOpacity(kShieldOpacity);
 }
 
 void WindowGrid::InitSelectionWidget(WindowSelector::Direction direction) {
@@ -820,9 +848,9 @@ void WindowGrid::InitSelectionWidget(WindowSelector::Direction direction) {
       material ? kWindowSelectionColorMD : kWindowSelectionColor;
   const int border_radius =
       material ? kWindowSelectionRadiusMD : kWindowSelectionRadius;
-  selection_widget_.reset(CreateBackgroundWidget(root_window_, selection_color,
-                                                 border_thickness,
-                                                 border_radius, border_color));
+  selection_widget_.reset(
+      CreateBackgroundWidget(root_window_, selection_color, border_thickness,
+                             border_radius, border_color, 0.f));
 
   WmWindow* widget_window =
       WmLookup::Get()->GetWindowForWidget(selection_widget_.get());