Use vector icon for Ash shelf launcher

ash/common/shelf/shelf_constants.h

 // Copyright 2013 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 ASH_COMMON_SHELF_SHELF_CONSTANTS_H_
 #define ASH_COMMON_SHELF_SHELF_CONSTANTS_H_
 
 #include "ash/ash_export.h"
 #include "third_party/skia/include/core/SkColor.h"
 
@@ skipping 18 matching lines @@
 // Size allocated for each button on the shelf.
 ASH_EXPORT extern const int kShelfButtonSize;
 
 // Animation duration for switching black shelf and dock background on and off.
 ASH_EXPORT extern const int kTimeToSwitchBackgroundMs;
 
 // The base color of the shelf to which different alpha values are applied
 // based on the desired shelf opacity level.
 ASH_EXPORT extern const SkColor kShelfBaseColor;
 
+// The foreground color of the icons used in the shelf (launcher,
+// notifications, etc).
+ASH_EXPORT extern const SkColor kShelfIconColor;
+
 // The direction of the focus cycling.
 enum CycleDirection { CYCLE_FORWARD, CYCLE_BACKWARD };
 
 ASH_EXPORT int GetShelfConstant(ShelfConstant shelf_constant);
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SHELF_SHELF_CONSTANTS_H_