Fix folder bounding box within apps container

The bounding box was calculated from apps container contents bounds by
setting y coordinate - this did not update the bounds height, so the
bounding box ended up being outside the apps container bounds.
Instead, the bounding box should be set by insetting the original, apps
container bounds.

BUG=1227493, 1227667

Change-Id: I5f2d30912e8fd1741ea5c13d7bd64cc5f0156c19
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3022568
Reviewed-by: Alex Newcomer <newcomer@chromium.org>
Commit-Queue: Toni Baržić <tbarzic@chromium.org>
Cr-Commit-Position: refs/heads/master@{#901040}

ash/app_list/views/apps_container_view.cc

@@ -58,8 +58,8 @@ constexpr int kNonAppsStateVerticalOffset = 24;
 // The opacity the apps container UI should have when shown on non apps page UI.
 constexpr float kNonAppsStateOpacity = 0.1;
 
-// The horizontal margin within the apps container for app list folder view.
-constexpr int kFolderHorizontalMargin = 8;
+// The margins within the apps container for app list folder view.
+constexpr int kFolderMargin = 8;
 
 }  // namespace
 
@@ -271,8 +271,8 @@ void AppsContainerView::Layout() {
   // Set bounding box for the folder view - the folder may overlap with
   // suggestion chips, but not the search box.
   gfx::Rect folder_bounding_box = rect;
-  folder_bounding_box.set_y(chip_container_rect.y());
-  folder_bounding_box.Inset(kFolderHorizontalMargin, 0);
+  folder_bounding_box.Inset(kFolderMargin, chip_container_rect.y(),
+                            kFolderMargin, kFolderMargin);
   app_list_folder_view_->SetBoundingBox(folder_bounding_box);
 
   // Leave the same available bounds for the apps grid view in both
@@ -282,7 +282,6 @@ void AppsContainerView::Layout() {
   rect.set_height(rect.height() -
                   GetExpectedSuggestionChipY(kAppListFullscreenProgressValue) -
                   chip_container_rect.height());
-
   const GridLayout grid_layout = CalculateGridLayout();
   apps_grid_view_->SetLayout(grid_layout.columns, grid_layout.rows);