Draggable peeking/fullscreen launcher with transparent background.

ash/shelf/shelf_layout_manager.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/shelf/shelf_layout_manager.h"
 
 #include <algorithm>
 #include <cmath>
 #include <vector>
 
@@ skipping 155 matching lines @@
 ShelfLayoutManager::~ShelfLayoutManager() {
   if (update_shelf_observer_)
     update_shelf_observer_->Detach();
 
   for (auto& observer : observers_)
     observer.WillDeleteShelfLayoutManager();
   Shell::Get()->RemoveShellObserver(this);
   ShellPort::Get()->RemoveLockStateObserver(this);
 }
 
+void ShelfLayoutManager::OnAppListIsActive(bool is_active) {
+  app_list_is_active_ = is_active;

[sky, 2017/05/31 15:04:17]

Is it really necessary to cache this state? Could it be looked up when
necessary?

[newcomer, 2017/06/01 01:42:54]

Done.

+  MaybeUpdateShelfBackground(AnimationChangeType::IMMEDIATE);
+}
+
 void ShelfLayoutManager::PrepareForShutdown() {
   in_shutdown_ = true;
   // Stop observing changes to avoid updating a partially destructed shelf.
   Shell::Get()->activation_client()->RemoveObserver(this);
 }
 
 bool ShelfLayoutManager::IsVisible() const {
   // status_area_widget() may be nullptr during the shutdown.
   return shelf_widget_->status_area_widget() &&
          shelf_widget_->status_area_widget()->IsVisible() &&
@@ skipping 275 matching lines @@
 }
 
 ShelfBackgroundType ShelfLayoutManager::GetShelfBackgroundType() const {
   if (state_.pre_lock_screen_animation_active)
     return SHELF_BACKGROUND_DEFAULT;
 
   // Handle all non active screen states, including OOBE and pre-login.
   if (state_.session_state != session_manager::SessionState::ACTIVE)
     return SHELF_BACKGROUND_OVERLAP;
 
+  // If the app list is active, hide the shelf background to prevent overlap.
+  if (app_list_is_active_)
+    return SHELF_BACKGROUND_DEFAULT;
+
   if (state_.visibility_state != SHELF_AUTO_HIDE &&
       state_.window_state == wm::WORKSPACE_WINDOW_STATE_MAXIMIZED) {
     return SHELF_BACKGROUND_MAXIMIZED;
   }
 
   if (gesture_drag_status_ == GESTURE_DRAG_IN_PROGRESS ||
       window_overlaps_shelf_ || state_.visibility_state == SHELF_AUTO_HIDE) {
     return SHELF_BACKGROUND_OVERLAP;
   }
 
@@ skipping 673 matching lines @@
   gesture_drag_status_ = GESTURE_DRAG_NONE;
 }
 
 void ShelfLayoutManager::CancelGestureDrag() {
   gesture_drag_status_ = GESTURE_DRAG_CANCEL_IN_PROGRESS;
   UpdateVisibilityState();
   gesture_drag_status_ = GESTURE_DRAG_NONE;
 }
 
 }  // namespace ash