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

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=sky@chromium.org

Bug: 1145565
Change-Id: I92bcf71a7f5296555933003d799fcb0fff7968e5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2548001
Auto-Submit: Sigurður Ásgeirsson <siggi@chromium.org>
Commit-Queue: Sigurður Ásgeirsson <siggi@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#828957}

chrome/browser/ui/views/bookmarks/bookmark_bar_view_test.cc

@@ -9,6 +9,8 @@
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
+#include "base/scoped_multi_source_observation.h"
+#include "base/scoped_observation.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
@@ -456,18 +458,18 @@ class BookmarkBarViewDragTestBase : public BookmarkBarViewEventTestBase,
 
   void OnWidgetDestroying(views::Widget* widget) override {
     if (widget == window())
-      bookmark_bar_observer_.RemoveAll();
+      bookmark_bar_observation_.RemoveObservation();
   }
 
   void OnWidgetDestroyed(views::Widget* widget) override {
-    widget_observer_.Remove(widget);
+    widget_observations_.RemoveObservation(widget);
   }
 
  protected:
   // BookmarkBarViewEventTestBase:
   void DoTestOnMessageLoop() override {
-    widget_observer_.Add(window());
-    bookmark_bar_observer_.Add(bb_view_);
+    widget_observations_.AddObservation(window());
+    bookmark_bar_observation_.Observe(bb_view_);
 
     // Record the URL for node f1a.
     const auto& f1 = model_->bookmark_bar_node()->children().front();
@@ -489,7 +491,7 @@ class BookmarkBarViewDragTestBase : public BookmarkBarViewEventTestBase,
     ASSERT_TRUE(submenu->IsShowing());
 
     // The menu is showing, so it has a widget we can observe now.
-    widget_observer_.Add(submenu->GetWidget());
+    widget_observations_.AddObservation(submenu->GetWidget());
 
     // Move mouse to center of node f1a and press button.
     views::View* f1a = submenu->GetMenuItemAt(0);
@@ -533,9 +535,10 @@ class BookmarkBarViewDragTestBase : public BookmarkBarViewEventTestBase,
   }
 
   GURL f1a_url_;
-  ScopedObserver<BookmarkBarView, BookmarkBarViewObserver>
-      bookmark_bar_observer_{this};
-  ScopedObserver<views::Widget, views::WidgetObserver> widget_observer_{this};
+  base::ScopedObservation<BookmarkBarView, BookmarkBarViewObserver>
+      bookmark_bar_observation_{this};
+  base::ScopedMultiSourceObservation<views::Widget, views::WidgetObserver>
+      widget_observations_{this};
 };
 
 #if !defined(OS_MAC)

chrome/browser/ui/views/bookmarks/bookmark_drag_drop_views.cc

@@ -6,6 +6,7 @@
 
 #include "base/bind.h"
 #include "base/no_destructor.h"
+#include "base/scoped_observation.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/task/current_thread.h"
 #include "base/threading/thread_task_runner_handle.h"
@@ -178,9 +179,8 @@ class BookmarkDragHelper : public bookmarks::BaseBookmarkModelObserver {
         source_(params.source),
         start_point_(params.start_point),
         do_drag_callback_(std::move(do_drag_callback)),
-        drag_data_(std::make_unique<ui::OSExchangeData>()),
-        observer_(this) {
-    observer_.Add(model_);
+        drag_data_(std::make_unique<ui::OSExchangeData>()){
+    observation_.Observe(model_);
 
     // Set up our OLE machinery.
     bookmarks::BookmarkNodeData bookmark_drag_data(params.nodes);
@@ -272,8 +272,9 @@ class BookmarkDragHelper : public bookmarks::BaseBookmarkModelObserver {
 
   std::unique_ptr<ui::OSExchangeData> drag_data_;
 
-  ScopedObserver<bookmarks::BookmarkModel, bookmarks::BookmarkModelObserver>
-      observer_;
+  base::ScopedObservation<bookmarks::BookmarkModel,
+                          bookmarks::BookmarkModelObserver>
+      observation_{this};
 
   base::WeakPtrFactory<BookmarkDragHelper> weak_factory_{this};