Fix app list duplication on drag.

ui/app_list/views/apps_grid_view.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/app_list/views/apps_grid_view.h"
 
 #include <algorithm>
 #include <set>
 #include <string>
 
@@ skipping 1382 matching lines @@
                                              Index* drop_target) const {
   Index nearest_tile_index(GetNearestTileIndexForPoint(point));
   int distance_to_tile_center =
       (point - GetExpectedTileBounds(nearest_tile_index.slot).CenterPoint())
           .Length();
   if (nearest_tile_index != reorder_placeholder_ &&
       distance_to_tile_center < kFolderDroppingCircleRadius &&
       !IsFolderItem(drag_view_->item()) &&
       CanDropIntoTarget(nearest_tile_index)) {
     *drop_target = nearest_tile_index;
+    DCHECK(IsValidIndex(*drop_target));
     return true;
   }
 
   return false;
 }
 
 void AppsGridView::CalculateReorderDropTarget(const gfx::Point& point,
                                               Index* drop_target) const {
   gfx::Rect bounds = GetContentsBounds();
   Index grid_index = GetNearestTileIndexForPoint(point);
@@ skipping 16 matching lines @@
   //
   // This makes eordering feel like the user is slotting items into the spaces
   // between apps.
   int x_offset = x_offset_direction *
                  (total_tile_size.width() - kFolderDroppingCircleRadius) / 2;
   int col = (point.x() - bounds.x() + x_offset) / total_tile_size.width();
   col = ClampToRange(col, 0, cols_ - 1);
   *drop_target =
       std::min(Index(pagination_model_.selected_page(), row * cols_ + col),
                GetLastViewIndex());
+  DCHECK(IsValidIndex(*drop_target));
 }
 
 void AppsGridView::OnReorderTimer() {
   if (drop_attempt_ == DROP_FOR_REORDER) {
     reorder_placeholder_ = reorder_drop_target_;
     AnimateToIdealBounds();
   }
 }
 
 void AppsGridView::OnFolderItemReparentTimer() {
@@ skipping 94 matching lines @@
   DCHECK(IsDraggingForReparentInRootLevelGridView());
   bool cancel_reparent = cancel_drag || drop_attempt_ == DROP_FOR_NONE;
   if (!events_forwarded_to_drag_drop_host && !cancel_reparent) {
     CalculateDropTarget();
     if (drop_attempt_ == DROP_FOR_REORDER &&
         IsValidIndex(reorder_drop_target_)) {
       ReparentItemForReorder(drag_view_, reorder_drop_target_);
     } else if (drop_attempt_ == DROP_FOR_FOLDER &&
                IsValidIndex(folder_drop_target_)) {
       ReparentItemToAnotherFolder(drag_view_, folder_drop_target_);
+    } else {
+      NOTREACHED();
     }
     SetViewHidden(drag_view_, false /* show */, true /* no animate */);
   }
 
   // The drag can be ended after the synchronous drag is created but before it
   // is Run().
   CleanUpSynchronousDrag();
 
   SetAsFolderDroppingTarget(folder_drop_target_, false);
   if (cancel_reparent) {
@@ skipping 525 matching lines @@
   // OEM folder does not allow to drag/drop other items in it.
   return target_item->ChildItemCount() < kMaxFolderItems &&
          !IsOEMFolderItem(target_item);
 }
 
 AppsGridView::Index AppsGridView::GetNearestTileIndexForPoint(
     const gfx::Point& point) const {
   gfx::Rect bounds = GetContentsBounds();
   gfx::Size total_tile_size = GetTotalTileSize();
   int col = ClampToRange(
-      (point.x() - bounds.x()) / total_tile_size.width(), 0, cols_);
-  int row = ClampToRange(
-      (point.y() - bounds.y()) / total_tile_size.height(), 0, rows_per_page_);
+      (point.x() - bounds.x()) / total_tile_size.width(), 0, cols_ - 1);
+  int row = ClampToRange((point.y() - bounds.y()) / total_tile_size.height(),
+                         0,
+                         rows_per_page_ - 1);
   return Index(pagination_model_.selected_page(), row * cols_ + col);
 }
 
 gfx::Size AppsGridView::GetTileGridSize() const {
   gfx::Rect bounds = GetExpectedTileBounds(0, 0);
   bounds.Union(GetExpectedTileBounds(rows_per_page_ - 1, cols_ - 1));
   if (switches::IsExperimentalAppListEnabled())
     bounds.Inset(-kExperimentalTileLeftRightPadding,
                  -kExperimentalTileTopBottomPadding);
   return bounds.size();
@@ skipping 33 matching lines @@
 void AppsGridView::SetAsFolderDroppingTarget(const Index& target_index,
                                              bool is_target_folder) {
   AppListItemView* target_view =
       static_cast<AppListItemView*>(
           GetViewAtSlotOnCurrentPage(target_index.slot));
   if (target_view)
     target_view->SetAsAttemptedFolderTarget(is_target_folder);
 }
 
 }  // namespace app_list