[MD] Implement incognito colors as a NativeTheme (for Aura).

ui/views/widget/widget.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_WIDGET_H_
 #define UI_VIEWS_WIDGET_WIDGET_H_
 
 #include <set>
 #include <stack>
 #include <vector>
@@ skipping 222 matching lines @@
     ui::WindowShowState show_state;
     gfx::NativeView parent;
     // Specifies the initial bounds of the Widget. Default is empty, which means
     // the NativeWidget may specify a default size. If the parent is specified,
     // |bounds| is in the parent's coordinate system. If the parent is not
     // specified, it's in screen's global coordinate system.
     gfx::Rect bounds;
     // When set, this value is used as the Widget's NativeWidget implementation.
     // The Widget will not construct a default one. Default is NULL.
     NativeWidget* native_widget;
+    // If provided, sets the native theme for this widget.
+    ui::NativeTheme* native_theme;
     // Aura-only. Provides a DesktopWindowTreeHost implementation to use instead
     // of the default one.
     // TODO(beng): Figure out if there's a better way to expose this, e.g. get
     // rid of NW subclasses and do this all via message handling.
     DesktopWindowTreeHost* desktop_window_tree_host;
     // Only used by NativeWidgetAura. Specifies the type of layer for the
     // aura::Window. Default is ui::LAYER_TEXTURED.
     ui::LayerType layer_type;
     // Only used by Aura. Provides a context window whose RootWindow is
     // consulted during widget creation to determine where in the Window
@@ skipping 599 matching lines @@
   // Sizes and positions the frameless window just after it is created.
   void SetInitialBoundsForFramelessWindow(const gfx::Rect& bounds);
 
   // Returns the bounds and "show" state from the delegate. Returns true if
   // the delegate wants to use a specified bounds.
   bool GetSavedWindowPlacement(gfx::Rect* bounds,
                                ui::WindowShowState* show_state);
 
   internal::NativeWidgetPrivate* native_widget_;
 
+  // If non-null, the native theme for this widget. Otherwise the native theme
+  // comes from |native_widget_|.
+  ui::NativeTheme* native_theme_;
+
   base::ObserverList<WidgetObserver> observers_;
 
   base::ObserverList<WidgetRemovalsObserver> removals_observers_;
 
   // Non-owned pointer to the Widget's delegate. If a NULL delegate is supplied
   // to Init() a default WidgetDelegate is created.
   WidgetDelegate* widget_delegate_;
 
   // The root of the View hierarchy attached to this window.
   // WARNING: see warning in tooltip_manager_ for ordering dependencies with
@@ skipping 87 matching lines @@
   bool movement_disabled_;
 
   ScopedObserver<ui::NativeTheme, ui::NativeThemeObserver> observer_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(Widget);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_WIDGET_H_