Remove unused observer from ReadLaterBubbleView

Bug: 1109316
Change-Id: Ieb94246f7aabc11a9a6092e67dba67a6610c4147
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2500451
Auto-Submit: Peter Boström <pbos@chromium.org>
Commit-Queue: Caroline Rising <corising@chromium.org>
Reviewed-by: Caroline Rising <corising@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821223}

chrome/browser/ui/views/read_later/read_later_bubble_view.cc

@@ -47,6 +47,3 @@ ReadLaterBubbleView::ReadLaterBubbleView(const Browser* browser,
     : WebBubbleDialogView(browser->profile(), anchor_view) {}
 
 ReadLaterBubbleView::~ReadLaterBubbleView() = default;
-
-void ReadLaterBubbleView::ReadingListModelLoaded(
-    const ReadingListModel* model) {}

chrome/browser/ui/views/read_later/read_later_bubble_view.h

@@ -14,8 +14,7 @@ class Browser;
 
 // This bubble view displays a list of read-later entries.
 // This class is only used with the kReadLater feature.
-class ReadLaterBubbleView : public views::WebBubbleDialogView,
-                            public ReadingListModelObserver {
+class ReadLaterBubbleView : public views::WebBubbleDialogView {
  public:
   // Displays the read-later dialog under |anchor_view|, attached to |browser|.
   static base::WeakPtr<ReadLaterBubbleView> Show(const Browser* browser,
@@ -27,9 +26,6 @@ class ReadLaterBubbleView : public views::WebBubbleDialogView,
   ~ReadLaterBubbleView() override;
 
  private:
-  // ReadingListModelObserver:
-  void ReadingListModelLoaded(const ReadingListModel* model) override;
-
   base::WeakPtrFactory<ReadLaterBubbleView> weak_factory_{this};
 };