linux_aura: Add a flag for experimenting with ARGB windows.

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h

 // 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.
 
 #ifndef UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_X11_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_X11_H_
 
 #include <X11/extensions/shape.h>
 #include <X11/Xlib.h>
 
@@ skipping 176 matching lines @@
   // and dispatched to that host instead.
   void DispatchTouchEvent(ui::TouchEvent* event);
 
   // Resets the window region for the current widget bounds if necessary.
   void ResetWindowRegion();
 
   // Serializes an image to the format used by _NET_WM_ICON.
   void SerializeImageRepresentation(const gfx::ImageSkiaRep& rep,
                                     std::vector<unsigned long>* data);
 
+  // Returns an 8888 ARGB visual. Can return NULL if there is no matching
+  // visual on this display.
+  Visual* GetARGBVisual();
+
   // See comment for variable open_windows_.
   static std::list<XID>& open_windows();
 
   // Map the window (shows it) taking into account the given |show_state|.
   void MapWindow(ui::WindowShowState show_state);
 
+  void SetWindowTransparency();
+
   // ui::PlatformEventDispatcher:
   virtual bool CanDispatchEvent(const ui::PlatformEvent& event) OVERRIDE;
   virtual uint32_t DispatchEvent(const ui::PlatformEvent& event) OVERRIDE;
 
   base::WeakPtrFactory<DesktopWindowTreeHostX11> close_widget_factory_;
 
   // X11 things
   // The display and the native X window hosting the root window.
   XDisplay* xdisplay_;
   ::Window xwindow_;
@@ skipping 26 matching lines @@
   // Local flag for fullscreen state to avoid a state mismatch between
   // server and local window_properties_ during app-initiated fullscreen.
   bool is_fullscreen_;
 
   // True if the window should stay on top of most other windows.
   bool is_always_on_top_;
 
   // True if the window has title-bar / borders provided by the window manager.
   bool use_native_frame_;
 
+  // Whether we used an ARGB visual for our window.
+  bool use_argb_visual_;
+
   scoped_ptr<DesktopDispatcherClient> dispatcher_client_;
 
   DesktopDragDropClientAuraX11* drag_drop_client_;
 
   // Current Aura cursor.
   gfx::NativeCursor current_cursor_;
 
   scoped_ptr<X11WindowEventFilter> x11_window_event_filter_;
   scoped_ptr<X11DesktopWindowMoveClient> x11_window_move_client_;
 
@@ skipping 35 matching lines @@
   // attention to the window or completely ignore the hint. We stop flashing
   // the frame when |xwindow_| gains focus or handles a mouse button event.
   bool urgency_hint_set_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopWindowTreeHostX11);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_WINDOW_TREE_HOST_X11_H_