Fix crash after Launcher drag/drop (take 2)

ui/app_list/views/apps_grid_view_unittest.cc

Index: ui/app_list/views/apps_grid_view_unittest.cc
diff --git a/ui/app_list/views/apps_grid_view_unittest.cc b/ui/app_list/views/apps_grid_view_unittest.cc
index e7edc45a51cc7dcf32d3b9dbe1b0116772153f64..41bf0944d475426f68e45287a0a6b0cb92a41ba2 100644
--- a/ui/app_list/views/apps_grid_view_unittest.cc
+++ b/ui/app_list/views/apps_grid_view_unittest.cc
@@ -140,6 +140,19 @@ class AppsGridViewTest : public views::ViewsTestBase {
     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,
@@ -149,16 +162,12 @@ class AppsGridViewTest : public views::ViewsTestBase {
 
     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;
   }
 
@@ -446,10 +455,7 @@ TEST_F(AppsGridViewTest, MouseDragMaxItemsInFolderWithMovement) {
 
   // 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.
@@ -458,6 +464,62 @@ TEST_F(AppsGridViewTest, MouseDragMaxItemsInFolderWithMovement) {
   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();