[Extensions Menu] Small cleanups in ExtensionsMenuView

Do a couple small cleanups in ExtensionsMenuView:
- Update includes and forward declarations (removing unused, adding
  missing)
- Add function comments
- Remove unused function CreateFixedSizeIconView() (the last usage was
  removed in crrev.com/7127b171)

Bug: None
Change-Id: I83513678011b6adf825377def47003a677e5fb17
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1879605
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: Peter Boström <pbos@chromium.org>
Reviewed-by: Charlene Yan <cyan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709315}

chrome/browser/ui/views/extensions/extensions_menu_view.cc

@@ -270,16 +270,6 @@ void ExtensionsMenuView::Hide() {
     g_extensions_dialog->GetWidget()->Close();
 }
 
-// static
-std::unique_ptr<views::ImageView>
-ExtensionsMenuView::CreateFixedSizeIconView() {
-  // Note that this size is larger than the 16dp extension icons as it needs to
-  // accommodate 24dp click-to-script badging and surrounding shadows.
-  auto image_view = std::make_unique<views::ImageView>();
-  image_view->SetPreferredSize(kExtensionsMenuIconSize);
-  return image_view;
-}
-
 ExtensionsMenuView* ExtensionsMenuView::GetExtensionsMenuViewForTesting() {
   return g_extensions_dialog;
 }

chrome/browser/ui/views/extensions/extensions_menu_view.h

@@ -6,7 +6,9 @@
 #define CHROME_BROWSER_UI_VIEWS_EXTENSIONS_EXTENSIONS_MENU_VIEW_H_
 
 #include <memory>
+#include <vector>
 
+#include "base/scoped_observer.h"
 #include "chrome/browser/ui/toolbar/toolbar_actions_model.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/views/bubble/bubble_dialog_delegate_view.h"
@@ -14,14 +16,16 @@
 
 namespace views {
 class Button;
-class ImageView;
+class View;
 }  // namespace views
 
+class Browser;
 class ExtensionsContainer;
 class ExtensionsMenuItemView;
 
 // This bubble view displays a list of user extensions and a button to get to
 // managing the user's extensions (chrome://extensions).
+// This class is only used with the kExtensionsToolbarMenu feature.
 class ExtensionsMenuView : public views::BubbleDialogDelegateView,
                            public ToolbarActionsModel::Observer {
  public:
@@ -32,13 +36,22 @@ class ExtensionsMenuView : public views::BubbleDialogDelegateView,
                      ExtensionsContainer* extensions_container);
   ~ExtensionsMenuView() override;
 
+  // Displays the ExtensionsMenu under |anchor_view|, attached to |browser|, and
+  // with the associated |extensions_container|.
+  // Only one menu is allowed to be shown at a time (outside of tests).
   static void ShowBubble(views::View* anchor_view,
                          Browser* browser,
                          ExtensionsContainer* extensions_container);
+
+  // Returns true if there is currently an ExtensionsMenuView showing (across
+  // all browsers and profiles).
   static bool IsShowing();
+
+  // Hides the currently-showing ExtensionsMenuView, if any exists.
   static void Hide();
+
+  // Returns the currently-showing ExtensionsMenuView, if any exists.
   static ExtensionsMenuView* GetExtensionsMenuViewForTesting();
-  static std::unique_ptr<views::ImageView> CreateFixedSizeIconView();
 
   // views::BubbleDialogDelegateView:
   base::string16 GetWindowTitle() const override;