Retire ScopedObserver in /chrome/browser/ui/views/tabs.

ScopedObserver is being deprecated in favor of two new classes:
- base::ScopedObservation for observers that only ever observe
  a single source.
- base::ScopedMultiSourceObservation for observers that do or may
  observe more than a single source.

This CL was uploaded by git cl split.

R=pkasting@chromium.org, tluk@chromium.org

Bug: 1145565
Change-Id: Ifb06297c295ec0b76e7380bc3d3787bc72a4b411
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2547776
Auto-Submit: Sigurður Ásgeirsson <siggi@chromium.org>
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#829257}

chrome/browser/ui/views/tabs/new_tab_button.h

@@ -5,7 +5,7 @@
 #ifndef CHROME_BROWSER_UI_VIEWS_TABS_NEW_TAB_BUTTON_H_
 #define CHROME_BROWSER_UI_VIEWS_TABS_NEW_TAB_BUTTON_H_
 
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "chrome/browser/ui/views/frame/browser_view.h"
 #include "chrome/browser/ui/views/tabs/tab_strip.h"
 #include "ui/views/controls/button/image_button.h"

chrome/browser/ui/views/tabs/tab.cc

@@ -17,7 +17,7 @@
 #include "base/metrics/user_metrics.h"
 #include "base/numerics/ranges.h"
 #include "base/numerics/safe_conversions.h"
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/time/time.h"
 #include "build/build_config.h"
@@ -146,13 +146,13 @@ class Tab::TabCloseButtonObserver : public views::ViewObserver {
                                   TabController* controller)
       : tab_(tab), close_button_(close_button), controller_(controller) {
     DCHECK(close_button_);
-    tab_close_button_observer_.Add(close_button_);
+    tab_close_button_observation_.Observe(close_button_);
   }
   TabCloseButtonObserver(const TabCloseButtonObserver&) = delete;
   TabCloseButtonObserver& operator=(const TabCloseButtonObserver&) = delete;
 
   ~TabCloseButtonObserver() override {
-    tab_close_button_observer_.Remove(close_button_);
+    tab_close_button_observation_.RemoveObservation();
   }
 
  private:
@@ -166,8 +166,8 @@ class Tab::TabCloseButtonObserver : public views::ViewObserver {
       controller_->UpdateHoverCard(nullptr);
   }
 
-  ScopedObserver<views::View, views::ViewObserver> tab_close_button_observer_{
-      this};
+  base::ScopedObservation<views::View, views::ViewObserver>
+      tab_close_button_observation_{this};
 
   Tab* tab_;
   views::View* close_button_;

chrome/browser/ui/views/tabs/tab_drag_controller.cc

@@ -412,7 +412,8 @@ TabDragController::~TabDragController() {
   if (g_tab_drag_controller == this)
     g_tab_drag_controller = nullptr;
 
-  widget_observer_.RemoveAll();
+  if (widget_observation_.IsObserving())
+    widget_observation_.RemoveObservation();
 
   if (is_dragging_window())
     GetAttachedBrowserWidget()->EndMoveLoop();
@@ -688,7 +689,8 @@ void TabDragController::OnWidgetBoundsChanged(views::Widget* widget,
 }
 
 void TabDragController::OnWidgetDestroyed(views::Widget* widget) {
-  widget_observer_.Remove(widget);
+  DCHECK(widget_observation_.IsObservingSource(widget));
+  widget_observation_.RemoveObservation();
 }
 
 void TabDragController::OnSourceTabStripEmpty() {
@@ -880,8 +882,8 @@ TabDragController::DragBrowserToNewTabStrip(TabDragContext* target_context,
     // results in a move). That'll cause all sorts of problems.  Reset the
     // observer so we don't get notified and process the event.
 #if defined(OS_CHROMEOS)
-    if (widget_observer_.IsObserving(move_loop_widget_))
-      widget_observer_.Remove(move_loop_widget_);
+    if (widget_observation_.IsObservingSource(move_loop_widget_))
+      widget_observation_.RemoveObservation();
     move_loop_widget_ = nullptr;
 #endif  // OS_CHROMEOS
     views::Widget* browser_widget = GetAttachedBrowserWidget();
@@ -1398,7 +1400,7 @@ void TabDragController::RunMoveLoop(const gfx::Vector2d& drag_offset) {
 
   move_loop_widget_ = GetAttachedBrowserWidget();
   DCHECK(move_loop_widget_);
-  widget_observer_.Add(move_loop_widget_);
+  widget_observation_.Observe(move_loop_widget_);
   current_state_ = DragState::kDraggingWindow;
   base::WeakPtr<TabDragController> ref(weak_factory_.GetWeakPtr());
   if (can_release_capture_) {
@@ -1427,8 +1429,10 @@ void TabDragController::RunMoveLoop(const gfx::Vector2d& drag_offset) {
   if (!ref)
     return;
 
-  if (widget_observer_.IsObserving(move_loop_widget_))
-    widget_observer_.Remove(move_loop_widget_);
+  if (move_loop_widget_ &&
+      widget_observation_.IsObservingSource(move_loop_widget_)) {
+    widget_observation_.RemoveObservation();
+  }
   move_loop_widget_ = nullptr;
 
   if (current_state_ == DragState::kDraggingWindow) {

chrome/browser/ui/views/tabs/tab_drag_controller.h

@@ -11,7 +11,7 @@
 #include <vector>
 
 #include "base/memory/weak_ptr.h"
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/ui/tabs/tab_strip_model_observer.h"
 #include "chrome/browser/ui/views/tabs/tab_drag_context.h"
@@ -693,7 +693,8 @@ class TabDragController : public views::WidgetObserver {
 
   std::unique_ptr<WindowFinder> window_finder_;
 
-  ScopedObserver<views::Widget, views::WidgetObserver> widget_observer_{this};
+  base::ScopedObservation<views::Widget, views::WidgetObserver>
+      widget_observation_{this};
 
   base::WeakPtrFactory<TabDragController> weak_factory_{this};
 };

chrome/browser/ui/views/tabs/tab_hover_card_bubble_view.cc

@@ -410,11 +410,12 @@ class TabHoverCardBubbleView::ThumbnailObserver
     if (current_image_ == thumbnail_image)
       return;
 
-    scoped_observer_.RemoveAll();
+    if (scoped_observation_.IsObserving())
+      scoped_observation_.RemoveObservation();
     current_image_ = std::move(thumbnail_image);
 
     if (current_image_) {
-      scoped_observer_.Add(current_image_.get());
+      scoped_observation_.Observe(current_image_.get());
       current_image_->RequestThumbnailImage();
     }
   }
@@ -434,8 +435,8 @@ class TabHoverCardBubbleView::ThumbnailObserver
 
   scoped_refptr<ThumbnailImage> current_image_;
   TabHoverCardBubbleView* const hover_card_;
-  ScopedObserver<ThumbnailImage, ThumbnailImage::Observer> scoped_observer_{
-      this};
+  base::ScopedObservation<ThumbnailImage, ThumbnailImage::Observer>
+      scoped_observation_{this};
 };
 
 TabHoverCardBubbleView::TabHoverCardBubbleView(Tab* tab)
@@ -547,7 +548,7 @@ TabHoverCardBubbleView::TabHoverCardBubbleView(Tab* tab)
       std::make_unique<WidgetSlideAnimationDelegate>(this);
   fade_animation_delegate_ =
       std::make_unique<WidgetFadeAnimationDelegate>(GetWidget());
-  thumbnail_observer_ = std::make_unique<ThumbnailObserver>(this);
+  thumbnail_observation_ = std::make_unique<ThumbnailObserver>(this);
 
   constexpr int kFootnoteVerticalMargin = 8;
   GetBubbleFrameView()->set_footnote_margins(
@@ -648,7 +649,7 @@ void TabHoverCardBubbleView::FadeOutToHide() {
   delayed_show_timer_.Stop();
   if (!GetWidget()->IsVisible())
     return;
-  thumbnail_observer_->Observe(nullptr);
+  thumbnail_observation_->Observe(nullptr);
   slide_animation_delegate_->StopAnimation();
   last_visible_timestamp_ = base::TimeTicks::Now();
   if (disable_animations_for_testing_) {
@@ -804,12 +805,12 @@ void TabHoverCardBubbleView::UpdateCardContent(const Tab* tab) {
       auto thumbnail = tab->data().thumbnail;
       if (!thumbnail) {
         ClearPreviewImage();
-      } else if (thumbnail != thumbnail_observer_->current_image()) {
+      } else if (thumbnail != thumbnail_observation_->current_image()) {
         waiting_for_decompress_ = true;
-        thumbnail_observer_->Observe(thumbnail);
+        thumbnail_observation_->Observe(thumbnail);
       }
     } else {
-      thumbnail_observer_->Observe(nullptr);
+      thumbnail_observation_->Observe(nullptr);
     }
   }
 }

chrome/browser/ui/views/tabs/tab_hover_card_bubble_view.h

@@ -7,7 +7,7 @@
 
 #include <memory>
 
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/ui/tabs/tab_utils.h"
@@ -99,7 +99,7 @@ class TabHoverCardBubbleView : public views::BubbleDialogDelegateView {
   std::unique_ptr<WidgetFadeAnimationDelegate> fade_animation_delegate_;
   // Used to animate the tab hover card's movement between tabs.
   std::unique_ptr<WidgetSlideAnimationDelegate> slide_animation_delegate_;
-  std::unique_ptr<ThumbnailObserver> thumbnail_observer_;
+  std::unique_ptr<ThumbnailObserver> thumbnail_observation_;
 
   // Timestamp of the last time a hover card was visible, recorded before it is
   // hidden. This is used for metrics.

chrome/browser/ui/views/tabs/tab_search_button.cc

@@ -96,7 +96,9 @@ void TabSearchButton::OnWidgetVisibilityChanged(views::Widget* widget,
 
 void TabSearchButton::OnWidgetDestroying(views::Widget* widget) {
   DCHECK_EQ(webui_bubble_manager_.GetBubbleWidget(), widget);
-  observed_bubble_widget_.Remove(webui_bubble_manager_.GetBubbleWidget());
+  DCHECK(bubble_widget_observation_.IsObservingSource(
+      webui_bubble_manager_.GetBubbleWidget()));
+  bubble_widget_observation_.RemoveObservation();
   pressed_lock_.reset();
 }
 
@@ -114,8 +116,8 @@ bool TabSearchButton::ShowTabSearchBubble(bool triggered_by_keyboard_shortcut) {
 
   // There should only ever be a single bubble widget active for the
   // TabSearchButton.
-  DCHECK(!observed_bubble_widget_.IsObservingSources());
-  observed_bubble_widget_.Add(webui_bubble_manager_.GetBubbleWidget());
+  DCHECK(!bubble_widget_observation_.IsObserving());
+  bubble_widget_observation_.Observe(webui_bubble_manager_.GetBubbleWidget());
   widget_open_timer_.Reset(webui_bubble_manager_.GetBubbleWidget());
 
   // Hold the pressed lock while the |bubble_| is active.

chrome/browser/ui/views/tabs/tab_search_button.h

@@ -80,8 +80,8 @@ class TabSearchButton : public NewTabButton,
   // in the process of being shown.
   std::unique_ptr<views::MenuButtonController::PressedLock> pressed_lock_;
 
-  ScopedObserver<views::Widget, views::WidgetObserver> observed_bubble_widget_{
-      this};
+  base::ScopedObservation<views::Widget, views::WidgetObserver>
+      bubble_widget_observation_{this};
 };
 
 #endif  // CHROME_BROWSER_UI_VIEWS_TABS_TAB_SEARCH_BUTTON_H_

chrome/browser/ui/views/tabs/tab_strip.cc

@@ -1029,7 +1029,8 @@ TabStrip::~TabStrip() {
   // but before moving the mouse.
   RemoveMessageLoopObserver();
 
-  hover_card_observer_.RemoveAll();
+  if (hover_card_observation_.IsObserving())
+    hover_card_observation_.RemoveObservation();
 
   // Since TabGroupViews expects be able to remove the views it creates, clear
   // |group_views_| before removing the remaining children below.
@@ -1937,7 +1938,7 @@ void TabStrip::UpdateHoverCard(Tab* tab) {
     if (!tab)
       return;
     hover_card_ = new TabHoverCardBubbleView(tab);
-    hover_card_observer_.Add(hover_card_);
+    hover_card_observation_.Observe(hover_card_);
     if (GetWidget()) {
       hover_card_event_sniffer_ =
           std::make_unique<TabHoverCardEventSniffer>(hover_card_, this);
@@ -3257,7 +3258,7 @@ TabStrip::DropArrow::DropArrow(const BrowserRootView::DropIndex& index,
   arrow_view_ =
       arrow_window_->SetContentsView(std::make_unique<views::ImageView>());
   arrow_view_->SetImage(GetDropArrowImage(point_down_));
-  scoped_observer_.Add(arrow_window_);
+  scoped_observation_.Observe(arrow_window_);
 
   arrow_window_->Show();
 }
@@ -3281,7 +3282,8 @@ void TabStrip::DropArrow::SetWindowBounds(const gfx::Rect& bounds) {
 }
 
 void TabStrip::DropArrow::OnWidgetDestroying(views::Widget* widget) {
-  scoped_observer_.Remove(arrow_window_);
+  DCHECK(scoped_observation_.IsObservingSource(arrow_window_));
+  scoped_observation_.RemoveObservation();
   arrow_window_ = nullptr;
 }
 
@@ -3621,7 +3623,8 @@ views::View* TabStrip::TargetForRect(views::View* root, const gfx::Rect& rect) {
 
 void TabStrip::OnViewIsDeleting(views::View* observed_view) {
   if (observed_view == hover_card_) {
-    hover_card_observer_.Remove(hover_card_);
+    DCHECK(hover_card_observation_.IsObservingSource(hover_card_));
+    hover_card_observation_.RemoveObservation();
     hover_card_event_sniffer_.reset();
     hover_card_ = nullptr;
   }

chrome/browser/ui/views/tabs/tab_strip.h

@@ -15,7 +15,7 @@
 #include "base/memory/ref_counted.h"
 #include "base/observer_list.h"
 #include "base/optional.h"
-#include "base/scoped_observer.h"
+#include "base/scoped_observation.h"
 #include "base/timer/timer.h"
 #include "build/build_config.h"
 #include "chrome/browser/ui/tabs/tab_types.h"
@@ -410,7 +410,8 @@ class TabStrip : public views::View,
 
     views::ImageView* arrow_view_ = nullptr;
 
-    ScopedObserver<views::Widget, views::WidgetObserver> scoped_observer_{this};
+    base::ScopedObservation<views::Widget, views::WidgetObserver>
+        scoped_observation_{this};
   };
 
   void Init();
@@ -665,7 +666,8 @@ class TabStrip : public views::View,
   // The view tracker is used to keep track of if the hover card has been
   // destroyed by its widget.
   TabHoverCardBubbleView* hover_card_ = nullptr;
-  ScopedObserver<views::View, views::ViewObserver> hover_card_observer_{this};
+  base::ScopedObservation<views::View, views::ViewObserver>
+      hover_card_observation_{this};
   std::unique_ptr<ui::EventHandler> hover_card_event_sniffer_;
 
   std::unique_ptr<TabStripController> controller_;