cros: Move container focus logic to shelf_focus_cycler

This will make it easier to consolidate the logic when the components
are split into different widgets.

Change-Id: I367bee362632ad015f73c1da8637ac71942bdc9e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1674657
Commit-Queue: Alex Newcomer <newcomer@chromium.org>
Reviewed-by: Jenny Zhang <jennyz@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672609}

ash/BUILD.gn

@@ -561,6 +561,8 @@ component("ash") {
     "shelf/shelf_control_button.h",
     "shelf/shelf_controller.cc",
     "shelf/shelf_controller.h",
+    "shelf/shelf_focus_cycler.cc",
+    "shelf/shelf_focus_cycler.h",
     "shelf/shelf_layout_manager.cc",
     "shelf/shelf_layout_manager.h",
     "shelf/shelf_layout_manager_observer.h",

ash/shelf/shelf.cc

@@ -15,6 +15,7 @@
 #include "ash/root_window_controller.h"
 #include "ash/shelf/shelf_bezel_event_handler.h"
 #include "ash/shelf/shelf_controller.h"
+#include "ash/shelf/shelf_focus_cycler.h"
 #include "ash/shelf/shelf_layout_manager.h"
 #include "ash/shelf/shelf_observer.h"
 #include "ash/shelf/shelf_widget.h"
@@ -60,7 +61,8 @@ class Shelf::AutoHideEventHandler : public ui::EventHandler {
 
 Shelf::Shelf()
     : shelf_locking_manager_(this),
-      bezel_event_handler_(std::make_unique<ShelfBezelEventHandler>(this)) {}
+      bezel_event_handler_(std::make_unique<ShelfBezelEventHandler>(this)),
+      shelf_focus_cycler_(std::make_unique<ShelfFocusCycler>(this)) {}
 
 Shelf::~Shelf() = default;
 

ash/shelf/shelf.h

@@ -31,6 +31,7 @@ namespace ash {
 
 enum class AnimationChangeType;
 class ShelfBezelEventHandler;
+class ShelfFocusCycler;
 class ShelfLayoutManager;
 class ShelfLayoutManagerTest;
 class ShelfLockingManager;
@@ -174,6 +175,9 @@ class ASH_EXPORT Shelf : public ShelfLayoutManagerObserver {
   ShelfAutoHideBehavior auto_hide_behavior() const {
     return auto_hide_behavior_;
   }
+
+  ShelfFocusCycler* shelf_focus_cycler() { return shelf_focus_cycler_.get(); }
+
   void set_is_tablet_mode_animation_running(bool value) {
     is_tablet_mode_animation_running_ = value;
   }
@@ -220,6 +224,9 @@ class ASH_EXPORT Shelf : public ShelfLayoutManagerObserver {
   // Forwards touch gestures on a bezel sensor to the shelf.
   std::unique_ptr<ShelfBezelEventHandler> bezel_event_handler_;
 
+  // Hands focus off to different parts of the shelf.
+  std::unique_ptr<ShelfFocusCycler> shelf_focus_cycler_;
+
   // True while the animation to enter or exit tablet mode is running. Sometimes
   // this value is true when the shelf movements are not actually animating
   // (animation value = 0.0). This is because this is set to true when we

ash/shelf/shelf_focus_cycler.cc

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "ash/shelf/shelf_focus_cycler.h"
+
+#include "ash/focus_cycler.h"
+#include "ash/shelf/login_shelf_view.h"
+#include "ash/shelf/shelf.h"
+#include "ash/shelf/shelf_widget.h"
+#include "ash/shell.h"
+#include "ash/system/status_area_widget.h"
+#include "ash/system/status_area_widget_delegate.h"
+#include "ash/system/tray/system_tray_notifier.h"
+
+namespace ash {
+
+ShelfFocusCycler::ShelfFocusCycler(Shelf* shelf) : shelf_(shelf) {}
+
+void ShelfFocusCycler::FocusOut(bool reverse, SourceView source_view) {
+  switch (source_view) {
+    case SourceView::kShelfView: {
+      StatusAreaWidget* status_area_widget = shelf_->GetStatusAreaWidget();
+      status_area_widget->status_area_widget_delegate()
+          ->set_default_last_focusable_child(reverse);
+      Shell::Get()->focus_cycler()->FocusWidget(status_area_widget);
+      break;
+    }
+    case SourceView::kSystemTrayView: {
+      // Focus can move to the shelf, or the focus will be delegated to system
+      // tray focus observers.
+      bool should_focus_shelf = true;
+      // If we are using a views-based shelf:
+      // * If we're in an active session, always bring focus to the shelf
+      //   whether we are going in reverse or not.
+      // * Otherwise (login/lock screen, OOBE), bring focus to the shelf only
+      //   if we're going in reverse; if we're going forward, let the system
+      //   tray focus observers focus the lock/login view.
+      ShelfWidget* shelf_widget = shelf_->shelf_widget();
+      if (shelf_widget->login_shelf_view()->GetVisible()) {
+        // Login/lock screen or OOBE.
+        should_focus_shelf = reverse;
+      }
+
+      if (should_focus_shelf) {
+        shelf_widget->set_default_last_focusable_child(reverse);
+        shelf_widget->set_activated_from_other_widget(true);
+        Shell::Get()->focus_cycler()->FocusWidget(shelf_widget);
+        shelf_widget->FocusFirstOrLastFocusableChild(reverse);
+      } else {
+        Shell::Get()->system_tray_notifier()->NotifyFocusOut(reverse);
+      }
+      break;
+    }
+  }
+}
+}  // namespace ash
\ No newline at end of file

ash/shelf/shelf_focus_cycler.h

+// Copyright (c) 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ASH_SHELF_SHELF_FOCUS_CYCLER_H_
+#define ASH_SHELF_SHELF_FOCUS_CYCLER_H_
+
+#include "base/macros.h"
+
+namespace ash {
+class Shelf;
+
+// The containers that rely on ShelfFocusCycler to move focus outside of their
+// view trees.
+enum class SourceView {
+  kShelfView = 0,
+  kSystemTrayView,
+};
+
+// ShelfFocusCycler handles the special focus transitions from the Login UI,
+// Shelf, and Status Tray.
+class ShelfFocusCycler {
+ public:
+  explicit ShelfFocusCycler(Shelf* shelf);
+  ~ShelfFocusCycler() = default;
+
+  // Moves focus from one container to the next. |reverse| will move the focus
+  // to the container to the left in LTR. RTL does not need to be accounted
+  // for when calling this function.
+  void FocusOut(bool reverse, SourceView source_view);
+
+ private:
+  // Owned by RootWindowController.
+  Shelf* shelf_;
+
+  DISALLOW_COPY_AND_ASSIGN(ShelfFocusCycler);
+};
+
+}  // namespace ash
+
+#endif  // ASH_SHELF_SHELF_FOCUS_CYCLER_H_

ash/shelf/shelf_view.cc

@@ -31,6 +31,7 @@
 #include "ash/shelf/shelf_constants.h"
 #include "ash/shelf/shelf_context_menu_model.h"
 #include "ash/shelf/shelf_controller.h"
+#include "ash/shelf/shelf_focus_cycler.h"
 #include "ash/shelf/shelf_menu_model_adapter.h"
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
@@ -38,8 +39,6 @@
 #include "ash/strings/grit/ash_strings.h"
 #include "ash/system/model/system_tray_model.h"
 #include "ash/system/model/virtual_keyboard_model.h"
-#include "ash/system/status_area_widget.h"
-#include "ash/system/status_area_widget_delegate.h"
 #include "ash/wm/mru_window_tracker.h"
 #include "ash/wm/root_window_finder.h"
 #include "ash/wm/tablet_mode/tablet_mode_controller.h"
@@ -885,18 +884,8 @@ void ShelfView::OnShelfButtonAboutToRequestFocusFromTabTraversal(
     return;
   }
 
-  // The logic here seems backwards, but is actually correct. For instance if
-  // the ShelfView's internal focus cycling logic attemmpts to focus the first
-  // child (e.g. app list button) after hitting Tab, we intercept that and
-  // instead, advance through to the status area.
-  if ((reverse && button == FindLastFocusableChild()) ||
-      (!reverse && button == FindFirstFocusableChild())) {
-    StatusAreaWidget* status_area_widget =
-        Shelf::ForWindow(GetWidget()->GetNativeWindow())->GetStatusAreaWidget();
-    status_area_widget->status_area_widget_delegate()
-        ->set_default_last_focusable_child(reverse);
-    Shell::Get()->focus_cycler()->FocusWidget(status_area_widget);
-  }
+  if (ShouldFocusOut(reverse, button))
+    shelf_->shelf_focus_cycler()->FocusOut(reverse, SourceView::kShelfView);
 }
 
 int64_t ShelfView::GetDisplayId() const {
@@ -1640,6 +1629,15 @@ bool ShelfView::SameDragType(ShelfItemType typea, ShelfItemType typeb) const {
   return false;
 }
 
+bool ShelfView::ShouldFocusOut(bool reverse, views::View* button) {
+  // The logic here seems backwards, but is actually correct. For instance if
+  // the ShelfView's internal focus cycling logic attemmpts to focus the first
+  // child (e.g. app list button) after hitting Tab, we intercept that and
+  // instead, advance through to the status area.
+  return (reverse && button == FindLastFocusableChild()) ||
+         (!reverse && button == FindFirstFocusableChild());
+}
+
 std::pair<int, int> ShelfView::GetDragRange(int index) {
   int min_index = -1;
   int max_index = -1;

ash/shelf/shelf_view.h

@@ -294,6 +294,7 @@ class ASH_EXPORT ShelfView : public views::View,
   // Returns the main shelf. This can be called on either the main shelf
   // or the overflow shelf.
   ShelfView* main_shelf() { return main_shelf_ ? main_shelf_ : this; }
+
   // Returns the overflow shelf. This can be called on either the main shelf
   // or the overflow shelf. Returns nullptr if the overflow shelf isn't visible.
   ShelfView* overflow_shelf() {
@@ -425,6 +426,9 @@ class ASH_EXPORT ShelfView : public views::View,
   // Returns true if |typea| and |typeb| should be in the same drag range.
   bool SameDragType(ShelfItemType typea, ShelfItemType typeb) const;
 
+  // Returns true if focus should move out of the ShelfView view tree.
+  bool ShouldFocusOut(bool reverse, views::View* button);
+
   // Returns the range (in the model) the item at the specified index can be
   // dragged to.
   std::pair<int, int> GetDragRange(int index);

ash/system/status_area_widget_delegate.cc

@@ -8,6 +8,7 @@
 #include "ash/root_window_controller.h"
 #include "ash/shelf/shelf.h"
 #include "ash/shelf/shelf_constants.h"
+#include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
 #include "ash/system/status_area_widget.h"
 #include "ash/system/tray/tray_constants.h"
@@ -65,6 +66,10 @@ void StatusAreaWidgetDelegate::SetFocusCyclerForTesting(
 }
 
 bool StatusAreaWidgetDelegate::ShouldFocusOut(bool reverse) {
+  // Never bring the focus out if it's not a views-based shelf as it is visually
+  // not on par with the status widget.
+  if (!ShelfWidget::IsUsingViewsShelf())
+    return false;
   views::View* focused_view = GetFocusManager()->GetFocusedView();
   return (reverse && focused_view == GetFirstFocusableChild()) ||
          (!reverse && focused_view == GetLastFocusableChild());

ash/system/tray/tray_background_view.cc

@@ -13,6 +13,7 @@
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/shelf/login_shelf_view.h"
 #include "ash/shelf/shelf_constants.h"
+#include "ash/shelf/shelf_focus_cycler.h"
 #include "ash/shelf/shelf_layout_manager.h"
 #include "ash/shelf/shelf_widget.h"
 #include "ash/shell.h"
@@ -270,37 +271,7 @@ void TrayBackgroundView::AboutToRequestFocusFromTabTraversal(bool reverse) {
   if (!delegate || !delegate->ShouldFocusOut(reverse))
     return;
 
-  // At this point, we know we should focus out of the status widget. It
-  // remains to be determined whether we should bring focus to the shelf, or
-  // whether we should delegate to system tray focus observers to decide
-  // where the focus goes next.
-  bool should_focus_shelf = true;
-
-  if (!ShelfWidget::IsUsingViewsShelf()) {
-    // Never bring the focus to the shelf if it's not a views-based shelf as
-    // it is visually not on par with the status widget.
-    return;
-  }
-
-  // If we are using a views-based shelf:
-  // * If we're in an active session, always bring focus to the shelf whether
-  //   we are going in reverse or not.
-  // * Otherwise (login/lock screen, OOBE), bring focus to the shelf only
-  //   if we're going in reverse; if we're going forward, let the system tray
-  //   focus observers focus the lock/login view.
-  if (shelf->shelf_widget()->login_shelf_view()->GetVisible()) {
-    // Login/lock screen or OOBE.
-    should_focus_shelf = reverse;
-  }
-
-  if (should_focus_shelf) {
-    shelf->shelf_widget()->set_default_last_focusable_child(reverse);
-    shelf->shelf_widget()->set_activated_from_other_widget(true);
-    Shell::Get()->focus_cycler()->FocusWidget(shelf->shelf_widget());
-    shelf->shelf_widget()->FocusFirstOrLastFocusableChild(reverse);
-  } else {
-    Shell::Get()->system_tray_notifier()->NotifyFocusOut(reverse);
-  }
+  shelf_->shelf_focus_cycler()->FocusOut(reverse, SourceView::kSystemTrayView);
 }
 
 void TrayBackgroundView::GetAccessibleNodeData(ui::AXNodeData* node_data) {