Show ItemWidget/Backdrop after overview animation ends.

Bug: 901402
Test: manual. The window title fades in after overview
  animation ends (in clamshell, tablet, from home launcher).
  and hides immediately when exiting.

Change-Id: I06b25ebea428439ec6e7ab2751db74409971855f
Reviewed-on: https://chromium-review.googlesource.com/c/1316363
Commit-Queue: Mitsuru Oshima <oshima@chromium.org>
Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Cr-Commit-Position: refs/heads/master@{#605578}

ash/wm/overview/scoped_transform_overview_window.cc

@@ -26,6 +26,7 @@
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "ui/aura/client/aura_constants.h"
+#include "ui/aura/null_window_targeter.h"
 #include "ui/aura/window.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_observer.h"
@@ -184,9 +185,15 @@ ScopedTransformOverviewWindow::ScopedTransformOverviewWindow(
       original_mask_layer_(window_->layer()->layer_mask_layer()),
       weak_ptr_factory_(this) {
   type_ = GetWindowDimensionsType(window);
+  original_targeter_ =
+      window_->SetEventTargeter(std::make_unique<aura::NullWindowTargeter>());
+  null_targeter_ = window_->targeter();
 }
 
 ScopedTransformOverviewWindow::~ScopedTransformOverviewWindow() {
+  if (null_targeter_ == window_->targeter())
+    window_->SetEventTargeter(std::move(original_targeter_));
+
   StopObservingImplicitAnimations();
 }
 

ash/wm/overview/scoped_transform_overview_window.h

@@ -20,6 +20,7 @@
 
 namespace aura {
 class Window;
+class WindowTargeter;
 }
 
 namespace gfx {
@@ -231,6 +232,15 @@ class ASH_EXPORT ScopedTransformOverviewWindow
   // The original mask layer of the window before entering overview mode.
   ui::Layer* original_mask_layer_ = nullptr;
 
+  // Stores the targeter for the window. For the duration of this object,
+  // |window_|'s event targeter will be replaced by a NullWindowTargeter to
+  // prevent events from reaching |window_|.
+  // TODO(sammiequon): Investigate if we can use a custom event targeter on
+  // windows for overview mode and remove the need for the extra widget which
+  // blocks events in WindowSelectorItem.
+  std::unique_ptr<aura::WindowTargeter> original_targeter_;
+  aura::WindowTargeter* null_targeter_ = nullptr;
+
   base::WeakPtrFactory<ScopedTransformOverviewWindow> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedTransformOverviewWindow);

ash/wm/overview/window_grid.cc

@@ -496,6 +496,9 @@ void WindowGrid::AddItem(aura::Window* window, bool reposition, bool animate) {
       window_list_.begin(),
       std::make_unique<WindowSelectorItem>(window, window_selector_, this));
   window_list_.front()->PrepareForOverview();
+  // The item is added after overview enter animation is complete, so
+  // just call OnStartingAnimationComplete.
+  window_list_.front()->OnStartingAnimationComplete();
 
   if (reposition)
     PositionWindows(animate);

ash/wm/overview/window_selector.cc

@@ -749,6 +749,10 @@ void WindowSelector::OnStartingAnimationComplete(bool canceled) {
     UpdateMaskAndShadow(!canceled);
     if (text_filter_widget_)
       text_filter_widget_->Show();
+    for (auto& grid : grid_list_) {
+      for (auto& window : grid->window_list())
+        window->OnStartingAnimationComplete();
+    }
   }
 }
 

ash/wm/overview/window_selector_item.cc

@@ -10,6 +10,7 @@
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/public/cpp/window_properties.h"
 #include "ash/resources/vector_icons/vector_icons.h"
+#include "ash/scoped_animation_disabler.h"
 #include "ash/shell.h"
 #include "ash/strings/grit/ash_strings.h"
 #include "ash/wm/overview/overview_animation_type.h"
@@ -137,6 +138,7 @@ std::unique_ptr<views::Widget> CreateBackdropWidget(aura::Window* parent) {
       /*border_thickness=*/0, kBackdropRoundingDp, kBackdropColor,
       /*initial_opacity=*/1.f, parent,
       /*stack_on_top=*/false);
+  widget->GetNativeWindow()->SetName("OverviewBackdrop");
   return widget;
 }
 
@@ -495,10 +497,6 @@ WindowSelectorItem::WindowSelectorItem(aura::Window* window,
       window_grid_(window_grid) {
   CreateWindowLabel(window->GetTitle());
   GetWindow()->AddObserver(this);
-  if (GetWindowDimensionsType() !=
-      ScopedTransformOverviewWindow::GridWindowFillMode::kNormal) {
-    backdrop_widget_ = CreateBackdropWidget(window->parent());
-  }
   GetWindow()->SetProperty(ash::kIsShowingInOverviewKey, true);
 }
 
@@ -564,15 +562,10 @@ void WindowSelectorItem::Shutdown() {
     return;
   }
 
-  // Fade out the item widget. This animation continues past the lifetime
-  // of |this|.
-  const bool slide = window_selector_->enter_exit_overview_type() ==
-                     WindowSelector::EnterExitOverviewType::kWindowsMinimized;
-  FadeOutWidgetAndMaybeSlideOnExit(
-      std::move(item_widget_),
-      slide ? OVERVIEW_ANIMATION_EXIT_TO_HOME_LAUNCHER
-            : OVERVIEW_ANIMATION_EXIT_OVERVIEW_MODE_FADE_OUT,
-      slide);
+  // Close the item widget without animation to reduce the load during exit
+  // animation.
+  ScopedAnimationDisabler(item_widget_->GetNativeWindow());
+  item_widget_.reset();
 }
 
 void WindowSelectorItem::PrepareForOverview() {
@@ -584,11 +577,8 @@ void WindowSelectorItem::PrepareForOverview() {
 void WindowSelectorItem::SlideWindowIn() {
   // |transform_window_|'s |minimized_widget| is non null because this only gets
   // called if we see the home launcher on enter (all windows are minimized).
-  DCHECK(item_widget_);
   DCHECK(transform_window_.minimized_widget());
-  FadeInWidgetAndMaybeSlideOnEnter(item_widget_.get(),
-                                   OVERVIEW_ANIMATION_ENTER_FROM_HOME_LAUNCHER,
-                                   /*slide=*/true);
+  // The |item_widget_| will be shown when animation ends.
   FadeInWidgetAndMaybeSlideOnEnter(transform_window_.minimized_widget(),
                                    OVERVIEW_ANIMATION_ENTER_FROM_HOME_LAUNCHER,
                                    /*slide=*/true);
@@ -793,6 +783,7 @@ WindowSelectorItem::GetWindowDimensionsType() const {
 }
 
 void WindowSelectorItem::UpdateWindowDimensionsType() {
+  // TODO(oshima|sammiequan|xdai): Use EnableBackdropIfNeeded.
   transform_window_.UpdateWindowDimensionsType();
   if (GetWindowDimensionsType() ==
       ScopedTransformOverviewWindow::GridWindowFillMode::kNormal) {
@@ -814,7 +805,10 @@ void WindowSelectorItem::EnableBackdropIfNeeded() {
     DisableBackdrop();
     return;
   }
-
+  if (!backdrop_widget_) {
+    backdrop_widget_ =
+        CreateBackdropWidget(transform_window_.window()->parent());
+  }
   UpdateBackdropBounds();
 }
 
@@ -1055,6 +1049,14 @@ void WindowSelectorItem::UpdateMaskAndShadow(bool show) {
   EnableBackdropIfNeeded();
 }
 
+void WindowSelectorItem::OnStartingAnimationComplete() {
+  DCHECK(item_widget_.get());
+  FadeInWidgetAndMaybeSlideOnEnter(
+      item_widget_.get(), OVERVIEW_ANIMATION_ENTER_OVERVIEW_MODE_FADE_IN,
+      /*slide=*/false);
+  EnableBackdropIfNeeded();
+}
+
 void WindowSelectorItem::SetOpacity(float opacity) {
   item_widget_->SetOpacity(opacity);
   transform_window_.SetOpacity(opacity);
@@ -1180,9 +1182,6 @@ void WindowSelectorItem::CreateWindowLabel(const base::string16& title) {
   item_widget_->Show();
   item_widget_->SetOpacity(0);
   item_widget_->GetLayer()->SetMasksToBounds(false);
-  FadeInWidgetAndMaybeSlideOnEnter(
-      item_widget_.get(), OVERVIEW_ANIMATION_ENTER_OVERVIEW_MODE_FADE_IN,
-      /*slide=*/false);
 }
 
 void WindowSelectorItem::UpdateHeaderLayout(

ash/wm/overview/window_selector_item.h

@@ -236,6 +236,10 @@ class ASH_EXPORT WindowSelectorItem : public views::ButtonListener,
   // Show or hide the mask and shadow on this window item.
   void UpdateMaskAndShadow(bool show);
 
+  // Called when the starting animation is completed, or called immediately
+  // if there was no starting animation.
+  void OnStartingAnimationComplete();
+
   // Changes the opacity of all the windows the item owns.
   void SetOpacity(float opacity);
   float GetOpacity();