Revert "CrOS Shelf: Start moving some hotseat logic into the hotseat widget"

This reverts commit d1531b9a.

Reason for revert:
Findit (https://goo.gl/kROfz5) identified CL at revision 711796 as the
culprit for failures in the build cycles as shown on:
https://analysis.chromium.org/waterfall/culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyRAsSDVdmU3VzcGVjdGVkQ0wiMWNocm9taXVtL2QxNTMxYjlhYzVhNDlkMTlmOTQ5ZTlkOGY0MmRhZjM0NzBkMzEzMmEM

Sample Failed Build: https://ci.chromium.org/b/8897957936228871696

Sample Failed Step: browser_tests

Original change's description:
> CrOS Shelf: Start moving some hotseat logic into the hotseat widget
>
> The general idea here is to encapsulate more of the hotseat's behavior
> into its own class rather than have it all over the shelf layout
> manager. Eventually, I hope to get rid of the huge
> "CalculateHotseatState" method by setting the hotseat state to the
> appropriate values from the relevant places.
>
> Change-Id: I03bf50bc9f6fb68f7f22f1b6ec966f08f48220da
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1893997
> Commit-Queue: Manu Cornet <manucornet@chromium.org>
> Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#711796}

TBR=xiyuan@chromium.org,manucornet@chromium.org

Change-Id: I7dd2357dd075bee067c3bad1aa58db788ba1039e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1893885Reviewed-by: Andy Paicu <andypaicu@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Commit-Queue: Andy Paicu <andypaicu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712119}

ash/shelf/hotseat_widget.cc

@@ -186,14 +186,6 @@ void HotseatWidget::Initialize(aura::Window* container, Shelf* shelf) {
   delegate_view_->Init(scrollable_shelf_view(), GetLayer());
 }
 
-void HotseatWidget::AddObserver(Observer* observer) {
-  observers_.AddObserver(observer);
-}
-
-void HotseatWidget::RemoveObserver(Observer* observer) {
-  observers_.RemoveObserver(observer);
-}
-
 void HotseatWidget::OnMouseEvent(ui::MouseEvent* event) {
   if (event->type() == ui::ET_MOUSE_PRESSED)
     keyboard::KeyboardUIController::Get()->HideKeyboardImplicitlyByUser();
@@ -239,15 +231,6 @@ const ShelfView* HotseatWidget::GetShelfView() const {
       const_cast<HotseatWidget*>(this)->GetShelfView());
 }
 
-void HotseatWidget::SetState(HotseatState state) {
-  if (state_ == state)
-    return;
-
-  state_ = state;
-  for (auto& observer : observers_)
-    observer.OnHotseatStateChanged();
-}
-
 bool HotseatWidget::IsShowingOverflowBubble() const {
   return GetShelfView()->IsShowingOverflowBubble();
 }

ash/shelf/hotseat_widget.h

@@ -7,9 +7,6 @@
 
 #include "ash/ash_export.h"
 #include "ash/public/cpp/shelf_config.h"
-#include "ash/public/cpp/shelf_types.h"
-#include "base/observer_list.h"
-#include "base/observer_list_types.h"
 #include "ui/views/widget/widget.h"
 
 namespace ash {
@@ -22,19 +19,12 @@ class ShelfView;
 class ASH_EXPORT HotseatWidget : public views::Widget,
                                  public ShelfConfig::Observer {
  public:
-  class Observer : public base::CheckedObserver {
-   public:
-    virtual void OnHotseatStateChanged() = 0;
-  };
   HotseatWidget();
   ~HotseatWidget() override;
 
   // Initializes the widget, sets its contents view and basic properties.
   void Initialize(aura::Window* container, Shelf* shelf);
 
-  void AddObserver(Observer* observer);
-  void RemoveObserver(Observer* observer);
-
   // views::Widget:
   void OnMouseEvent(ui::MouseEvent* event) override;
   void OnGestureEvent(ui::GestureEvent* event) override;
@@ -68,9 +58,6 @@ class ASH_EXPORT HotseatWidget : public views::Widget,
   ShelfView* GetShelfView();
   const ShelfView* GetShelfView() const;
 
-  void SetState(HotseatState state);
-  HotseatState state() const { return state_; }
-
   ScrollableShelfView* scrollable_shelf_view() {
     return scrollable_shelf_view_;
   }
@@ -95,10 +82,6 @@ class ASH_EXPORT HotseatWidget : public views::Widget,
   // of the hotseat.
   DelegateView* delegate_view_ = nullptr;
 
-  HotseatState state_ = HotseatState::kShown;
-
-  base::ObserverList<Observer> observers_;
-
   // Whether the widget is currently extended because the user has manually
   // dragged it. This will be reset with any visible shelf configuration change.
   bool is_manually_extended_ = false;

ash/shelf/shelf_layout_manager.h

@@ -14,7 +14,6 @@
 #include "ash/public/cpp/wallpaper_controller_observer.h"
 #include "ash/session/session_observer.h"
 #include "ash/shelf/shelf.h"
-#include "ash/shelf/shelf_widget.h"
 #include "ash/shell_observer.h"
 #include "ash/system/locale/locale_update_controller_impl.h"
 #include "ash/wm/desks/desks_controller.h"
@@ -65,7 +64,6 @@ class ASH_EXPORT ShelfLayoutManager : public AppListControllerObserver,
                                       public ShellObserver,
                                       public SplitViewObserver,
                                       public OverviewObserver,
-                                      public HotseatWidget::Observer,
                                       public ::wm::ActivationChangeObserver,
                                       public LockStateObserver,
                                       public WmDefaultLayoutManager,
@@ -121,7 +119,7 @@ class ASH_EXPORT ShelfLayoutManager : public AppListControllerObserver,
   void ProcessGestureEventOfAutoHideShelf(ui::GestureEvent* event,
                                           aura::Window* target);
 
-  // Handles events that are detected while the hotseat is extended in in-app
+  // Handles events that are detected while the hotseat is kExtended in in-app
   // shelf.
   void ProcessGestureEventOfInAppHotseat(ui::GestureEvent* event,
                                          aura::Window* target);
@@ -189,9 +187,6 @@ class ASH_EXPORT ShelfLayoutManager : public AppListControllerObserver,
   void OnOverviewModeEndingAnimationComplete(bool canceled) override;
   void OnOverviewModeEnded() override;
 
-  // HotseatWidget::Observer:
-  void OnHotseatStateChanged() override;
-
   // AppListControllerObserver:
   void OnAppListVisibilityWillChange(bool shown, int64_t display_id) override;
   void OnAppListVisibilityChanged(bool shown, int64_t display_id) override;
@@ -237,9 +232,7 @@ class ASH_EXPORT ShelfLayoutManager : public AppListControllerObserver,
 
   bool updating_bounds() const { return updating_bounds_; }
   ShelfAutoHideState auto_hide_state() const { return state_.auto_hide_state; }
-  HotseatState hotseat_state() const {
-    return shelf_widget_->hotseat_widget()->state();
-  }
+  HotseatState hotseat_state() const { return state_.hotseat_state; }
 
   DragWindowFromShelfController* window_drag_controller_for_testing() {
     return window_drag_controller_.get();

ash/shelf/shelf_layout_manager_observer.h

@@ -30,6 +30,9 @@ class ASH_EXPORT ShelfLayoutManagerObserver {
   virtual void OnBackgroundUpdated(ShelfBackgroundType background_type,
                                    AnimationChangeType change_type) {}
 
+  // Called when the hotseat state changes.
+  virtual void OnHotseatStateChanged(HotseatState state) {}
+
   // Called when ShelfLayoutManager has updated Shelf insets in work area
   // insets.
   virtual void OnWorkAreaInsetsChanged() {}

ash/shelf/shelf_layout_manager_unittest.cc

@@ -3219,16 +3219,19 @@ class HotseatShelfLayoutManagerTest
 };
 
 // Records HotseatState transitions.
-class HotseatStateWatcher : public HotseatWidget::Observer {
+class HotseatStateWatcher : public ShelfLayoutManagerObserver {
  public:
-  explicit HotseatStateWatcher(HotseatWidget* widget) : widget_(widget) {
-    widget_->AddObserver(this);
+  HotseatStateWatcher(ShelfLayoutManager* shelf_layout_manager)
+      : shelf_layout_manager_(shelf_layout_manager) {
+    shelf_layout_manager_->AddObserver(this);
+  }
+  ~HotseatStateWatcher() override {
+    shelf_layout_manager_->RemoveObserver(this);
   }
-  ~HotseatStateWatcher() override { widget_->RemoveObserver(this); }
 
-  void OnHotseatStateChanged() override {
+  void OnHotseatStateChanged(HotseatState state) override {
     run_loop_.QuitWhenIdle();
-    state_changes_.push_back(widget_->state());
+    state_changes_.push_back(state);
   }
 
   void CheckEqual(std::vector<HotseatState> state_changes) {
@@ -3238,7 +3241,7 @@ class HotseatStateWatcher : public HotseatWidget::Observer {
   void WaitUntilStateChanged() { run_loop_.Run(); }
 
  private:
-  HotseatWidget* const widget_;
+  ShelfLayoutManager* shelf_layout_manager_;
   std::vector<HotseatState> state_changes_;
   base::RunLoop run_loop_;
   DISALLOW_COPY_AND_ASSIGN(HotseatStateWatcher);
@@ -3536,8 +3539,8 @@ TEST_F(HotseatShelfLayoutManagerTest, ReleasingSlowDragBelowThreshold) {
   EXPECT_EQ(HotseatState::kHidden, GetShelfLayoutManager()->hotseat_state());
 }
 
-// Tests that releasing the hotseat gesture above the threshold results in an
-// extended hotseat.
+// Tests that releasing the hotseat gesture above the threshold results in a
+// kExtended hotseat.
 TEST_P(HotseatShelfLayoutManagerTest, ReleasingSlowDragAboveThreshold) {
   GetPrimaryShelf()->SetAutoHideBehavior(GetParam());
   TabletModeControllerTestApi().EnterTabletMode();
@@ -3574,8 +3577,7 @@ TEST_P(HotseatShelfLayoutManagerTest, ShowingOverviewFromShownAnimatesOnce) {
   wm::ActivateWindow(window.get());
 
   std::unique_ptr<HotseatStateWatcher> state_watcher_ =
-      std::make_unique<HotseatStateWatcher>(
-          GetPrimaryShelf()->shelf_widget()->hotseat_widget());
+      std::make_unique<HotseatStateWatcher>(GetShelfLayoutManager());
   SwipeUpOnShelf();
   ASSERT_EQ(HotseatState::kExtended, GetShelfLayoutManager()->hotseat_state());
 
@@ -3779,8 +3781,7 @@ TEST_P(HotseatShelfLayoutManagerTest, HomeToOverviewChangesStateOnce) {
                                                 .CenterPoint();
 
   {
-    HotseatStateWatcher watcher(
-        GetPrimaryShelf()->shelf_widget()->hotseat_widget());
+    HotseatStateWatcher watcher(GetShelfLayoutManager());
     OverviewAnimationWaiter waiter;
     GetEventGenerator()->GestureTapAt(overview_button_center);
     waiter.Wait();
@@ -3799,8 +3800,7 @@ TEST_P(HotseatShelfLayoutManagerTest, HomeToOverviewChangesStateOnce) {
   GetAppListTestHelper()->CheckVisibility(true);
   // Activate overview and expect the hotseat only changes state to extended.
   {
-    HotseatStateWatcher watcher(
-        GetPrimaryShelf()->shelf_widget()->hotseat_widget());
+    HotseatStateWatcher watcher(GetShelfLayoutManager());
     OverviewAnimationWaiter waiter;
     GetEventGenerator()->GestureTapAt(overview_button_center);
     waiter.Wait();
@@ -3815,8 +3815,7 @@ TEST_P(HotseatShelfLayoutManagerTest, HomeToInAppChangesStateOnce) {
   TabletModeControllerTestApi().EnterTabletMode();
 
   // Go to in-app, the hotseat should hide.
-  HotseatStateWatcher watcher(
-      GetPrimaryShelf()->shelf_widget()->hotseat_widget());
+  HotseatStateWatcher watcher(GetShelfLayoutManager());
   std::unique_ptr<aura::Window> window =
       AshTestBase::CreateTestWindow(gfx::Rect(0, 0, 400, 400));
   wm::ActivateWindow(window.get());
@@ -3840,8 +3839,7 @@ TEST_P(HotseatShelfLayoutManagerTest, InAppToHomeChangesStateOnce) {
   // Press the HomeLauncher button, the hotseat should transition directly to
   // kShown.
   {
-    HotseatStateWatcher watcher(
-        GetPrimaryShelf()->shelf_widget()->hotseat_widget());
+    HotseatStateWatcher watcher(GetShelfLayoutManager());
     views::View* home_button =
         GetPrimaryShelf()->shelf_widget()->GetHomeButton();
     GetEventGenerator()->GestureTapAt(
@@ -3859,8 +3857,7 @@ TEST_P(HotseatShelfLayoutManagerTest, InAppToHomeChangesStateOnce) {
   {
     ui::ScopedAnimationDurationScaleMode regular_animations(
         ui::ScopedAnimationDurationScaleMode::NON_ZERO_DURATION);
-    HotseatStateWatcher watcher(
-        GetPrimaryShelf()->shelf_widget()->hotseat_widget());
+    HotseatStateWatcher watcher(GetShelfLayoutManager());
     FlingUpOnShelf();
     watcher.WaitUntilStateChanged();
     watcher.CheckEqual({HotseatState::kShown});
@@ -3877,8 +3874,7 @@ TEST_P(HotseatShelfLayoutManagerTest, InAppToHomeChangesStateOnce) {
   // Press the HomeLauncher button, the hotseat should transition directly to
   // kShown.
   {
-    HotseatStateWatcher watcher(
-        GetPrimaryShelf()->shelf_widget()->hotseat_widget());
+    HotseatStateWatcher watcher(GetShelfLayoutManager());
     views::View* home_button =
         GetPrimaryShelf()->shelf_widget()->GetHomeButton();
     GetEventGenerator()->GestureTapAt(
@@ -3901,8 +3897,7 @@ TEST_F(HotseatShelfLayoutManagerTest,
       AshTestBase::CreateTestWindow(gfx::Rect(0, 0, 400, 400));
   wm::ActivateWindow(window.get());
   {
-    HotseatStateWatcher watcher(
-        GetPrimaryShelf()->shelf_widget()->hotseat_widget());
+    HotseatStateWatcher watcher(GetShelfLayoutManager());
     // Enter overview by using the controller.
     OverviewAnimationWaiter waiter;
     Shell::Get()->overview_controller()->StartOverview();
@@ -3922,8 +3917,7 @@ TEST_F(HotseatShelfLayoutManagerTest,
             GetShelfLayoutManager()->auto_hide_state());
   SwipeUpOnShelf();
   {
-    HotseatStateWatcher watcher(
-        GetPrimaryShelf()->shelf_widget()->hotseat_widget());
+    HotseatStateWatcher watcher(GetShelfLayoutManager());
     // Enter overview by using the controller.
     OverviewAnimationWaiter waiter;
     Shell::Get()->overview_controller()->StartOverview();