views: don't allow bookmark menus to be repositioned next to the anchor

Doing this prevents easy "scrubbing" through the bookmark bar menus, since the
newly-appearing menu draws over the top of the adjacent bookmark buttons.

Bug: 902344
Change-Id: Ief783f4b417810416821b717f92f796b4e6b07e6
Reviewed-on: https://chromium-review.googlesource.com/c/1335870
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#608049}

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

@@ -188,6 +188,13 @@ void BookmarkMenuController::BookmarkModelChanged() {
     menu()->Cancel();
 }
 
+bool BookmarkMenuController::ShouldTryPositioningBesideAnchor() const {
+  // The bookmark menu appears from the bookmark bar, which has a set of buttons positioned next to
+  // each other; if the bookmark menu appears beside its anchor button, it will likely overlay the
+  // adjacent bookmark button, which prevents easy scrubbing through the bookmark bar's menus.
+  return false;
+}
+
 BookmarkMenuController::~BookmarkMenuController() {
   menu_delegate_->GetBookmarkModel()->RemoveObserver(this);
   if (observer_)

chrome/browser/ui/views/bookmarks/bookmark_menu_controller_views.h

@@ -114,6 +114,7 @@ class BookmarkMenuController : public bookmarks::BaseBookmarkModelObserver,
                                       views::MenuButton** button) override;
   int GetMaxWidthForMenu(views::MenuItemView* view) override;
   void WillShowMenu(views::MenuItemView* menu) override;
+  bool ShouldTryPositioningBesideAnchor() const override;
 
   // bookmarks::BaseBookmarkModelObserver:
   void BookmarkModelChanged() override;

ui/views/controls/menu/menu_controller.cc

@@ -2156,7 +2156,7 @@ gfx::Rect MenuController::CalculateMenuBounds(MenuItemView* item,
       // Menu fits above anchor bounds.
       menu_bounds.set_y(above_anchor);
       item->set_actual_menu_position(MenuItemView::POSITION_ABOVE_BOUNDS);
-    } else {
+    } else if (item->GetDelegate()->ShouldTryPositioningBesideAnchor()) {
       const int left_of_anchor = anchor_bounds.x() - menu_bounds.width();
       const int right_of_anchor = anchor_bounds.right();
 
@@ -2174,6 +2174,11 @@ gfx::Rect MenuController::CalculateMenuBounds(MenuItemView* item,
         if (menu_bounds.x() < monitor_bounds.x())
           menu_bounds.set_x(right_of_anchor);
       }
+    } else {
+      // The delegate doesn't want the menu repositioned to the side, and it
+      // doesn't fit on the screen in any orientation - just clip the menu to
+      // the screen and let the scrolling arrows appear.
+      menu_bounds.Intersect(monitor_bounds);
     }
   }
 

ui/views/controls/menu/menu_delegate.cc

@@ -152,4 +152,8 @@ bool MenuDelegate::ShouldReserveSpaceForSubmenuIndicator() const {
   return true;
 }
 
+bool MenuDelegate::ShouldTryPositioningBesideAnchor() const {
+  return true;
+}
+
 }  // namespace views

ui/views/controls/menu/menu_delegate.h

@@ -233,6 +233,11 @@ class VIEWS_EXPORT MenuDelegate {
   // Returns true if the labels should reserve additional spacing for e.g.
   // submenu indicators at the end of the line.
   virtual bool ShouldReserveSpaceForSubmenuIndicator() const;
+
+  // Returns true if menus should fall back to positioning beside the anchor,
+  // rather than directly above or below it, when the menu is too tall to fit
+  // within the screen.
+  virtual bool ShouldTryPositioningBesideAnchor() const;
 };
 
 }  // namespace views