ash::ShelfView: CHECK against potentially bad static_casts.

ash/shelf/shelf_view.cc

Index: ash/shelf/shelf_view.cc
diff --git a/ash/shelf/shelf_view.cc b/ash/shelf/shelf_view.cc
index 0fd7a01774cdd96990fabb58ba4de2be130a7933..42545c714b8dacc1fcda101f61be301d24ad2b5f 100644
--- a/ash/shelf/shelf_view.cc
+++ b/ash/shelf/shelf_view.cc
@@ -462,7 +462,9 @@ gfx::Rect ShelfView::GetIdealBoundsOfItemIcon(ShelfID id) {
     index = last_visible_index_ + 1;
   const gfx::Rect& ideal_bounds(view_model_->ideal_bounds(index));
   DCHECK_NE(TYPE_APP_LIST, model_->items()[index].type);
-  ShelfButton* button = static_cast<ShelfButton*>(view_model_->view_at(index));
+  views::View* view = view_model_->view_at(index);
+  CHECK_EQ(ShelfButton::kViewClassName, view->GetClassName());
+  ShelfButton* button = static_cast<ShelfButton*>(view);
   gfx::Rect icon_bounds = button->GetIconBounds();
   return gfx::Rect(GetMirroredXWithWidthInView(
                        ideal_bounds.x() + icon_bounds.x(), icon_bounds.width()),
@@ -1068,9 +1070,8 @@ bool ShelfView::HandleRipOffDrag(const ui::LocatedEvent& event) {
   int delta = CalculateShelfDistance(screen_location);
   if (delta > kRipOffDistance) {
     // Create a proxy view item which can be moved anywhere.
-    ShelfButton* button = static_cast<ShelfButton*>(drag_view_);
     CreateDragIconProxy(event.root_location(),
-                        button->GetImage(),
+                        drag_view_->GetImage(),
                         drag_view_,
                         gfx::Vector2d(0, 0),
                         kDragAndDropProxyScale);
@@ -1152,8 +1153,7 @@ void ShelfView::FinalizeRipOffDrag(bool cancel) {
       // animation end the flag gets cleared if |snap_back_from_rip_off_view_|
       // is set.
       snap_back_from_rip_off_view_ = drag_view_;
-      ShelfButton* button = static_cast<ShelfButton*>(drag_view_);
-      button->AddState(ShelfButton::STATE_HIDDEN);
+      drag_view_->AddState(ShelfButton::STATE_HIDDEN);
       // When a canceling drag model is happening, the view model is diverged
       // from the menu model and movements / animations should not be done.
       model_->Move(current_index, start_drag_index_);
@@ -1528,6 +1528,7 @@ void ShelfView::ShelfItemChanged(int model_index, const ShelfItem& old_item) {
     case TYPE_PLATFORM_APP:
     case TYPE_DIALOG:
     case TYPE_APP_PANEL: {
+      CHECK_EQ(ShelfButton::kViewClassName, view->GetClassName());
       ShelfButton* button = static_cast<ShelfButton*>(view);
       ReflectItemStatus(item, button);
       // The browser shortcut is currently not a "real" item and as such the
@@ -1572,7 +1573,8 @@ void ShelfView::PointerPressedOnButton(views::View* view,
   if (view_model_->view_size() <= 1 || !item_delegate->IsDraggable())
     return;  // View is being deleted or not draggable, ignore request.
 
-  drag_view_ = view;
+  CHECK_EQ(ShelfButton::kViewClassName, view->GetClassName());
+  drag_view_ = static_cast<ShelfButton*>(view);
   drag_origin_ = gfx::Point(event.x(), event.y());
   UMA_HISTOGRAM_ENUMERATION("Ash.ShelfAlignmentUsage",
       layout_manager_->SelectValueForShelfAlignment(
@@ -1866,6 +1868,7 @@ void ShelfView::OnBoundsAnimatorDone(views::BoundsAnimator* animator) {
       for (int index = 0; index < view_model_->view_size(); index++) {
         views::View* view = view_model_->view_at(index);
         if (view == snap_back_from_rip_off_view_) {
+          CHECK_EQ(ShelfButton::kViewClassName, view->GetClassName());
           ShelfButton* button = static_cast<ShelfButton*>(view);
           button->ClearState(ShelfButton::STATE_HIDDEN);
           break;