Draggable peeking/fullscreen launcher with transparent background.

ash/shell.h

Index: ash/shell.h
diff --git a/ash/shell.h b/ash/shell.h
index f4aa13a9d688aa1a1955cf3004a27b9164b5c23e..1e877ecd3f8e9a9f7bf8357cfd06bd5e836f2504 100644
--- a/ash/shell.h
+++ b/ash/shell.h
@@ -18,6 +18,7 @@
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
+#include "ui/app_list/presenter/app_list_delegate.h"
 #include "ui/aura/window.h"
 #include "ui/display/screen.h"
 #include "ui/events/event_target.h"
@@ -91,7 +92,6 @@ namespace ash {
 
 class AcceleratorController;
 class AccessibilityDelegate;
-class AppListDelegateImpl;
 class AshNativeCursorManager;
 class AshTouchTransformController;
 class AutoclickController;
@@ -193,7 +193,8 @@ class SmsObserverTest;
 class ASH_EXPORT Shell : public SessionObserver,
                          public SystemModalContainerEventFilterDelegate,
                          public ui::EventTarget,
-                         public ::wm::ActivationChangeObserver {
+                         public ::wm::ActivationChangeObserver,
+                         public app_list::AppListDelegate {
  public:
   typedef std::vector<RootWindowController*> RootWindowControllerList;
 
@@ -559,6 +560,9 @@ class ASH_EXPORT Shell : public SessionObserver,
   // TODO(oshima): Investigate if we can merge this and |OnLoginStateChanged|.
   void UpdateAfterLoginStatusChange(LoginStatus status);
 
+  // Notifies observers that the AppList has been shown or dismissed.
+  void NotifyAppListShownOrDismissed(bool shown, aura::Window* root_window);
+
   // Notifies observers that maximize mode has started, windows might still
   // animate.
   void NotifyMaximizeModeStarted();
@@ -647,6 +651,9 @@ class ASH_EXPORT Shell : public SessionObserver,
                          aura::Window* gained_active,
                          aura::Window* lost_active) override;
 
+  // Overridden from app_list::AppListDelegate:
+  void OnAppListVisibilityChanged(bool visible, int64_t display_id_) override;
+
   // SessionObserver:
   void OnSessionStateChanged(session_manager::SessionState state) override;
   void OnLoginStatusChanged(LoginStatus login_status) override;
@@ -821,8 +828,6 @@ class ASH_EXPORT Shell : public SessionObserver,
 
   std::unique_ptr<ImmersiveHandlerFactoryAsh> immersive_handler_factory_;
 
-  std::unique_ptr<AppListDelegateImpl> app_list_delegate_impl_;
-
   base::ObserverList<ShellObserver> shell_observers_;
 
   scoped_refptr<base::SequencedWorkerPool> blocking_pool_;