Draggable peeking/fullscreen launcher with transparent background.

ash/app_list/app_list_presenter_delegate.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 "ash/app_list/app_list_presenter_delegate.h"
 
 #include "ash/ash_switches.h"
 #include "ash/public/cpp/shelf_types.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/root_window_controller.h"
@@ skipping 111 matching lines @@
 
 void AppListPresenterDelegate::OnShown(int64_t display_id) {
   is_visible_ = true;
   // Update applist button status when app list visibility is changed.
   aura::Window* root_window =
       ShellPort::Get()->GetRootWindowForDisplayId(display_id);
   AppListButton* app_list_button =
       Shelf::ForWindow(root_window)->shelf_widget()->GetAppListButton();
   if (app_list_button)
     app_list_button->OnAppListShown();
+
+  // Notify the shelf that the app list is active so the backgrounds do not
+  // overlap.
+

[xiyuan, 2017/05/30 16:32:33]

nit: get rid of the empty line. And maybe move the comment inside "if" similar
to what we have in OnDismissed().

[newcomer, 2017/05/30 21:37:03]

Done.

+  if (app_list::features::IsFullscreenAppListEnabled()) {
+    Shelf* shelf = Shelf::ForWindow(root_window);
+    shelf->OnAppListIsActive(true);
+  }
 }
 
 void AppListPresenterDelegate::OnDismissed() {
   DCHECK(is_visible_);
   DCHECK(view_);
 
   is_visible_ = false;
 
   // Update applist button status when app list visibility is changed.
   Shelf* shelf = Shelf::ForWindow(view_->GetWidget()->GetNativeWindow());
   AppListButton* app_list_button = shelf->shelf_widget()->GetAppListButton();
   if (app_list_button)
     app_list_button->OnAppListDismissed();
+  if (app_list::features::IsFullscreenAppListEnabled()) {
+    // Notify the shelf that the app list is being dismissed so it can
+    // re-enable its transparent background.
+    shelf->OnAppListIsActive(false);
+  }
 }
 
 void AppListPresenterDelegate::UpdateBounds() {
   if (!view_ || !is_visible_)
     return;
 
   view_->UpdateBounds();
   view_->MaybeSetAnchorPoint(GetCenterOfDisplayForWindow(
       WmWindow::Get(view_->GetWidget()->GetNativeWindow()),
       GetMinimumBoundsHeightForAppList(view_)));
@@ skipping 85 matching lines @@
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // AppListPresenterDelegate, ShelfObserver implementation:
 
 void AppListPresenterDelegate::OnShelfIconPositionsChanged() {
   UpdateBounds();
 }
 
 }  // namespace ash