Use ScopedObserver where feasible in ui/views/accessibility, and view_tracker.{h,cc}.

This CL changes some classes in ui/views/accessibility/ and view_tracker.{h,cc} to use ScopedObserver.

Bug: https://bugs.chromium.org/p/chromium/issues/detail?id=940796
Change-Id: Iee16691098fae2e3cba4f11a9d970181ca28f659
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1558558
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714983}

chrome/browser/ui/views/tab_contents/chrome_web_contents_view_focus_helper.cc

@@ -56,14 +56,14 @@ bool ChromeWebContentsViewFocusHelper::TakeFocus(bool reverse) {
 }
 
 void ChromeWebContentsViewFocusHelper::StoreFocus() {
-  last_focused_view_tracker_.Clear();
+  last_focused_view_tracker_.SetView(nullptr);
   if (GetFocusManager())
     last_focused_view_tracker_.SetView(GetFocusManager()->GetFocusedView());
 }
 
 bool ChromeWebContentsViewFocusHelper::RestoreFocus() {
   views::View* view_to_focus = GetStoredFocus();
-  last_focused_view_tracker_.Clear();
+  last_focused_view_tracker_.SetView(nullptr);
   if (view_to_focus) {
     view_to_focus->RequestFocus();
     return true;
@@ -72,7 +72,7 @@ bool ChromeWebContentsViewFocusHelper::RestoreFocus() {
 }
 
 void ChromeWebContentsViewFocusHelper::ResetStoredFocus() {
-  last_focused_view_tracker_.Clear();
+  last_focused_view_tracker_.SetView(nullptr);
 }
 
 views::View* ChromeWebContentsViewFocusHelper::GetStoredFocus() {

ui/views/accessibility/accessibility_alert_window.cc

@@ -6,7 +6,6 @@
 
 #include "base/strings/utf_string_conversions.h"
 #include "ui/accessibility/platform/aura_window_properties.h"
-#include "ui/aura/env.h"
 #include "ui/aura/window.h"
 #include "ui/compositor/layer_type.h"
 #include "ui/views/accessibility/ax_aura_obj_cache.h"
@@ -24,12 +23,10 @@ AccessibilityAlertWindow::AccessibilityAlertWindow(aura::Window* parent,
   alert_window_->Init(ui::LayerType::LAYER_NOT_DRAWN);
   alert_window_->SetProperty(ui::kAXRoleOverride, ax::mojom::Role::kAlert);
   parent->AddChild(alert_window_.get());
-  aura::Env::GetInstance()->AddObserver(this);
+  observer_.Add(aura::Env::GetInstance());
 }
 
-AccessibilityAlertWindow::~AccessibilityAlertWindow() {
-  aura::Env::GetInstance()->RemoveObserver(this);
-}
+AccessibilityAlertWindow::~AccessibilityAlertWindow() = default;
 
 void AccessibilityAlertWindow::HandleAlert(const std::string& alert_string) {
   if (!alert_window_->parent())
@@ -40,10 +37,8 @@ void AccessibilityAlertWindow::HandleAlert(const std::string& alert_string) {
                     ax::mojom::Event::kAlert);
 }
 
-void AccessibilityAlertWindow::OnWindowInitialized(aura::Window* window) {}
-
 void AccessibilityAlertWindow::OnWillDestroyEnv() {
+  observer_.RemoveAll();
   alert_window_.reset();
 }
-
 }  // namespace views

ui/views/accessibility/accessibility_alert_window.h

@@ -8,6 +8,8 @@
 #include <memory>
 #include <string>
 
+#include "base/scoped_observer.h"
+#include "ui/aura/env.h"
 #include "ui/aura/env_observer.h"
 #include "ui/views/views_export.h"
 
@@ -34,7 +36,6 @@ class VIEWS_EXPORT AccessibilityAlertWindow : public aura::EnvObserver {
 
  private:
   // aura::EnvObserver:
-  void OnWindowInitialized(aura::Window* window) override;
   void OnWillDestroyEnv() override;
 
   // The child alert window.
@@ -42,6 +43,8 @@ class VIEWS_EXPORT AccessibilityAlertWindow : public aura::EnvObserver {
 
   // The accessibility cache associated with |alert_window_|.
   views::AXAuraObjCache* cache_;
+
+  ScopedObserver<aura::Env, aura::EnvObserver> observer_{this};
 };
 
 }  // namespace views

ui/views/accessibility/ax_view_obj_wrapper.cc

@@ -10,7 +10,6 @@
 #include "ui/views/accessibility/ax_aura_obj_cache.h"
 #include "ui/views/accessibility/ax_virtual_view.h"
 #include "ui/views/accessibility/view_accessibility.h"
-#include "ui/views/view.h"
 #include "ui/views/widget/widget.h"
 
 namespace views {
@@ -19,15 +18,10 @@ AXViewObjWrapper::AXViewObjWrapper(AXAuraObjCache* aura_obj_cache, View* view)
     : AXAuraObjWrapper(aura_obj_cache), view_(view) {
   if (view->GetWidget())
     aura_obj_cache_->GetOrCreate(view->GetWidget());
-  view->AddObserver(this);
+  observer_.Add(view);
 }
 
-AXViewObjWrapper::~AXViewObjWrapper() {
-  if (view_) {
-    view_->RemoveObserver(this);
-    view_ = nullptr;
-  }
-}
+AXViewObjWrapper::~AXViewObjWrapper() = default;
 
 bool AXViewObjWrapper::IsIgnored() {
   return view_ ? view_->GetViewAccessibility().IsIgnored() : true;
@@ -97,6 +91,7 @@ bool AXViewObjWrapper::HandleAccessibleAction(const ui::AXActionData& action) {
 }
 
 void AXViewObjWrapper::OnViewIsDeleting(View* observed_view) {
+  observer_.RemoveAll();
   view_ = nullptr;
 }
 

ui/views/accessibility/ax_view_obj_wrapper.h

@@ -7,12 +7,13 @@
 
 #include <stdint.h>
 
+#include "base/scoped_observer.h"
 #include "ui/views/accessibility/ax_aura_obj_wrapper.h"
+#include "ui/views/view.h"
 #include "ui/views/view_observer.h"
 
 namespace views {
 class AXAuraObjCache;
-class View;
 
 // Describes a |View| for use with other AX classes.
 class AXViewObjWrapper : public AXAuraObjWrapper, public ViewObserver {
@@ -38,6 +39,8 @@ class AXViewObjWrapper : public AXAuraObjWrapper, public ViewObserver {
 
  private:
   View* view_;
+
+  ScopedObserver<View, ViewObserver> observer_{this};
 };
 
 }  // namespace views

ui/views/accessibility/ax_widget_obj_wrapper.cc

@@ -4,12 +4,13 @@
 
 #include "ui/views/accessibility/ax_widget_obj_wrapper.h"
 
+#include <vector>
+
 #include "base/strings/utf_string_conversions.h"
 #include "ui/accessibility/ax_enums.mojom.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/views/accessibility/ax_aura_obj_cache.h"
 #include "ui/views/accessibility/ax_aura_obj_wrapper.h"
-#include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_delegate.h"
 
 namespace views {
@@ -17,12 +18,11 @@ namespace views {
 AXWidgetObjWrapper::AXWidgetObjWrapper(AXAuraObjCache* aura_obj_cache,
                                        Widget* widget)
     : AXAuraObjWrapper(aura_obj_cache), widget_(widget) {
-  widget->AddObserver(this);
+  widget_observer_.Add(widget);
   widget->AddRemovalsObserver(this);
 }
 
 AXWidgetObjWrapper::~AXWidgetObjWrapper() {
-  widget_->RemoveObserver(this);
   widget_->RemoveRemovalsObserver(this);
 }
 

ui/views/accessibility/ax_widget_obj_wrapper.h

@@ -7,14 +7,15 @@
 
 #include <stdint.h>
 
+#include "base/scoped_observer.h"
 #include "ui/accessibility/platform/ax_unique_id.h"
 #include "ui/views/accessibility/ax_aura_obj_wrapper.h"
+#include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_observer.h"
 #include "ui/views/widget/widget_removals_observer.h"
 
 namespace views {
 class AXAuraObjCache;
-class Widget;
 
 // Describes a |Widget| for use with other AX classes.
 class AXWidgetObjWrapper : public AXAuraObjWrapper,
@@ -46,6 +47,8 @@ class AXWidgetObjWrapper : public AXAuraObjWrapper,
   Widget* widget_;
 
   const ui::AXUniqueId unique_id_;
+
+  ScopedObserver<Widget, WidgetObserver> widget_observer_{this};
 };
 
 }  // namespace views

ui/views/accessibility/ax_window_obj_wrapper.cc

@@ -12,7 +12,6 @@
 #include "ui/accessibility/ax_tree_id.h"
 #include "ui/accessibility/platform/aura_window_properties.h"
 #include "ui/aura/client/focus_client.h"
-#include "ui/aura/window.h"
 #include "ui/views/accessibility/ax_aura_obj_cache.h"
 #include "ui/views/widget/widget.h"
 
@@ -66,15 +65,13 @@ AXWindowObjWrapper::AXWindowObjWrapper(AXAuraObjCache* aura_obj_cache,
     : AXAuraObjWrapper(aura_obj_cache),
       window_(window),
       is_root_window_(window->IsRootWindow()) {
-  window->AddObserver(this);
+  observer_.Add(window);
 
   if (is_root_window_)
     aura_obj_cache_->OnRootWindowObjCreated(window);
 }
 
-AXWindowObjWrapper::~AXWindowObjWrapper() {
-  window_->RemoveObserver(this);
-}
+AXWindowObjWrapper::~AXWindowObjWrapper() = default;
 
 bool AXWindowObjWrapper::IsIgnored() {
   return false;

ui/views/accessibility/ax_window_obj_wrapper.h

@@ -7,15 +7,13 @@
 
 #include <stdint.h>
 
+#include "base/scoped_observer.h"
 #include "ui/accessibility/ax_enums.mojom-forward.h"
 #include "ui/accessibility/platform/ax_unique_id.h"
+#include "ui/aura/window.h"
 #include "ui/aura/window_observer.h"
 #include "ui/views/accessibility/ax_aura_obj_wrapper.h"
 
-namespace aura {
-class Window;
-}  // namespace aura
-
 namespace views {
 class AXAuraObjCache;
 
@@ -61,6 +59,8 @@ class AXWindowObjWrapper : public AXAuraObjWrapper,
   bool is_root_window_;
 
   const ui::AXUniqueId unique_id_;
+
+  ScopedObserver<aura::Window, aura::WindowObserver> observer_{this};
 };
 
 }  // namespace views

ui/views/controls/menu/menu_controller.cc

@@ -2914,7 +2914,7 @@ void MenuController::SendMouseReleaseToActiveView(SubmenuView* event_source,
                                event.changed_button_flags());
   // Reset the active mouse view before sending mouse released. That way if it
   // calls back to us, we aren't in a weird state.
-  active_mouse_view_tracker_->Clear();
+  active_mouse_view_tracker_->SetView(nullptr);
   active_mouse_view->OnMouseReleased(release_event);
 }
 
@@ -2925,7 +2925,7 @@ void MenuController::SendMouseCaptureLostToActiveView() {
 
   // Reset the active mouse view before sending mouse capture lost. That way if
   // it calls back to us, we aren't in a weird state.
-  active_mouse_view_tracker_->Clear();
+  active_mouse_view_tracker_->SetView(nullptr);
   active_mouse_view->OnMouseCaptureLost();
 }
 

ui/views/view_tracker.cc

@@ -4,27 +4,22 @@
 
 #include "ui/views/view_tracker.h"
 
-#include "ui/views/view.h"
-
 namespace views {
 
 ViewTracker::ViewTracker(View* view) {
   SetView(view);
 }
 
-ViewTracker::~ViewTracker() {
-  SetView(nullptr);
-}
+ViewTracker::~ViewTracker() = default;
 
 void ViewTracker::SetView(View* view) {
   if (view == view_)
     return;
 
-  if (view_)
-    view_->RemoveObserver(this);
+  observer_.RemoveAll();
   view_ = view;
   if (view_)
-    view_->AddObserver(this);
+    observer_.Add(view_);
 }
 
 void ViewTracker::OnViewIsDeleting(View* observed_view) {

ui/views/view_tracker.h

@@ -5,20 +5,21 @@
 #ifndef UI_VIEWS_VIEW_TRACKER_H_
 #define UI_VIEWS_VIEW_TRACKER_H_
 
-#include "base/macros.h"
+#include "base/scoped_observer.h"
+#include "ui/views/view.h"
 #include "ui/views/view_observer.h"
 #include "ui/views/views_export.h"
 
 namespace views {
-
 // ViewTracker tracks a single View. When the View is deleted it's removed.
 class VIEWS_EXPORT ViewTracker : public ViewObserver {
  public:
   explicit ViewTracker(View* view = nullptr);
+  ViewTracker(const ViewTracker&) = delete;
+  ViewTracker& operator=(const ViewTracker&) = delete;
   ~ViewTracker() override;
 
   void SetView(View* view);
-  void Clear() { SetView(nullptr); }
   View* view() { return view_; }
 
   // ViewObserver:
@@ -27,7 +28,7 @@ class VIEWS_EXPORT ViewTracker : public ViewObserver {
  private:
   View* view_ = nullptr;
 
-  DISALLOW_COPY_AND_ASSIGN(ViewTracker);
+  ScopedObserver<View, ViewObserver> observer_{this};
 };
 
 }  // namespace views