Fix crash after Launcher drag/drop

ui/app_list/views/apps_grid_view_unittest.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 <string>
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
@@ skipping 122 matching lines @@
     gfx::Rect rect(gfx::Point(insets.left(), insets.top()),
                    AppsGridView::GetTotalTileSize());
     rect.Offset(col * rect.width(), row * rect.height());
     return rect;
   }
 
   PaginationModel* GetPaginationModel() {
     return apps_grid_view_->pagination_model();
   }
 
+  // Point is in |apps_grid_view_|'s coordinates.
+  void SimulateContinueDrag(AppsGridView::Pointer pointer,
+                            const AppListItemView* view,
+                            const gfx::Point& to) {
+    DCHECK(view);
+
+    gfx::Point translated_to =
+        gfx::PointAtOffsetFromOrigin(to - view->bounds().origin());
+
+    ui::MouseEvent drag_event(ui::ET_MOUSE_DRAGGED, translated_to, to, 0, 0);
+    apps_grid_view_->UpdateDragFromItem(pointer, drag_event);
+  }
+
   // Points are in |apps_grid_view_|'s coordinates.
   AppListItemView* SimulateDrag(AppsGridView::Pointer pointer,
                                 const gfx::Point& from,
                                 const gfx::Point& to) {
     AppListItemView* view = GetItemViewForPoint(from);
     DCHECK(view);
 
     gfx::Point translated_from = gfx::PointAtOffsetFromOrigin(
         from - view->bounds().origin());
-    gfx::Point translated_to = gfx::PointAtOffsetFromOrigin(
-        to - view->bounds().origin());
 
     ui::MouseEvent pressed_event(ui::ET_MOUSE_PRESSED,
                                  translated_from, from, 0, 0);
     apps_grid_view_->InitiateDrag(view, pointer, pressed_event);
 
-    ui::MouseEvent drag_event(ui::ET_MOUSE_DRAGGED,
-                              translated_to, to, 0, 0);
-    apps_grid_view_->UpdateDragFromItem(pointer, drag_event);
+    SimulateContinueDrag(pointer, view, to);
     return view;
   }
 
   void SimulateKeyPress(ui::KeyboardCode key_code) {
     ui::KeyEvent key_event(ui::ET_KEY_PRESSED, key_code, ui::EF_NONE);
     apps_grid_view_->OnKeyPressed(key_event);
   }
 
   scoped_ptr<AppListTestModel> model_;
   scoped_ptr<AppsGridView> apps_grid_view_;
@@ skipping 267 matching lines @@
   AppListItemView* dragged_view = SimulateDrag(AppsGridView::MOUSE, from, to);
   test_api_->LayoutToIdealBounds();
 
   // The grid now looks like | blank | folder |.
   EXPECT_EQ(NULL, GetItemViewForPoint(GetItemTileRectAt(0, 0).CenterPoint()));
   EXPECT_EQ(folder_view,
             GetItemViewForPoint(GetItemTileRectAt(0, 1).CenterPoint()));
 
   // Move onto the folder and end the drag.
   to = GetItemTileRectAt(0, 1).CenterPoint();
-  gfx::Point translated_to =
-      gfx::PointAtOffsetFromOrigin(to - dragged_view->bounds().origin());
-  ui::MouseEvent drag_event(ui::ET_MOUSE_DRAGGED, translated_to, to, 0, 0);
-  apps_grid_view_->UpdateDragFromItem(AppsGridView::MOUSE, drag_event);
+  SimulateContinueDrag(AppsGridView::MOUSE, dragged_view, to);
   apps_grid_view_->EndDrag(false);
 
   // The item should not have moved into the folder.
   EXPECT_EQ(2u, model_->top_level_item_list()->item_count());
   EXPECT_EQ(kMaxFolderItems, folder_item->ChildItemCount());
   test_api_->LayoutToIdealBounds();
 }
 
+// Drag item into solitary folder on 2nd page.  This fails to test Issue 439055,
+// because there's no |drag_and_drop_host_| to enter the offending code block in
+// AppsGridView::EndDrag(), but we'll keep it as a useful edge case test.
+TEST_F(AppsGridViewTest, MouseDragItemIntoLonelyFolder) {
+  EnsureFoldersEnabled();
+
+  size_t kTotalItems = kTilesPerPage + 1;
+  model_->PopulateApps(kTilesPerPage);
+  model_->CreateAndPopulateFolderWithApps(2);
+  EXPECT_EQ(kTotalItems, model_->top_level_item_list()->item_count());
+  EXPECT_EQ(2, GetPaginationModel()->total_pages());
+  EXPECT_EQ(
+      AppListFolderItem::kItemType,
+      model_->top_level_item_list()->item_at(kTilesPerPage)->GetItemType());
+  EXPECT_EQ(0, GetPaginationModel()->selected_page());
+
+  // Set up page switching
+  test_api_->SetPageFlipDelay(10);
+  // NOTE: We lower |duration_ms| arg to 0.  During slow valgrind tests, the
+  // drag-and-hover would push the target folder into the empty space on the
+  // first page, leaving nothing to drop the item on, and foiling the test.
+  GetPaginationModel()->SetTransitionDurations(0, 10);
+  PageFlipWaiter page_flip_waiter(message_loop(), GetPaginationModel());
+
+  gfx::Point from = GetItemTileRectAt(0, 0).CenterPoint();
+  gfx::Point to =
+      gfx::Point(apps_grid_view_->width(), apps_grid_view_->height() / 2);
+
+  // Drag to right edge, page should flip
+  page_flip_waiter.Reset();
+  AppListItemView* view = SimulateDrag(AppsGridView::MOUSE, from, to);
+  while (test_api_->HasPendingPageFlip()) {
+    page_flip_waiter.Wait();
+  }
+  EXPECT_EQ(1, GetPaginationModel()->selected_page());
+
+  // Continue drag to lonely folder, then drop
+  to = GetItemTileRectAt(0, 0).CenterPoint();
+  AppListItemView* folder = GetItemViewForPoint(to);
+  EXPECT_NE(nullptr, folder);
+  if (folder) {
+    EXPECT_EQ(AppListFolderItem::kItemType, folder->item()->GetItemType());
+    SimulateContinueDrag(AppsGridView::MOUSE, view, to);
+  }
+  apps_grid_view_->EndDrag(false);
+
+  // Moving item from first page to folder should shift folder to first page
+  EXPECT_EQ(1, GetPaginationModel()->total_pages());
+  EXPECT_EQ(0, GetPaginationModel()->selected_page());
+  EXPECT_EQ(kTotalItems - 1, model_->top_level_item_list()->item_count());
+  EXPECT_EQ(
+      AppListFolderItem::kItemType,
+      model_->top_level_item_list()->item_at(kTilesPerPage - 1)->GetItemType());
+  test_api_->LayoutToIdealBounds();
+}
+
 TEST_F(AppsGridViewTest, MouseDragItemReorder) {
   // This test assumes Folders are enabled.
   EnsureFoldersEnabled();
 
   model_->PopulateApps(4);
   EXPECT_EQ(4u, model_->top_level_item_list()->item_count());
   EXPECT_EQ(std::string("Item 0,Item 1,Item 2,Item 3"),
             model_->GetModelContent());
 
   // Dragging an item towards its neighbours should not reorder until the drag
@@ skipping 311 matching lines @@
   AppListItemView* item_view = GetItemViewAt(0);
   ASSERT_TRUE(item_view);
   const views::Label* title_label = item_view->title();
   EXPECT_FALSE(title_label->GetTooltipText(
       title_label->bounds().CenterPoint(), &actual_tooltip));
   EXPECT_EQ(title, base::UTF16ToUTF8(title_label->text()));
 }
 
 }  // namespace test
 }  // namespace app_list