Update shelf spacing in Chrome OS according to the MD specs

ash/common/system/tray/tray_constants.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 ASH_COMMON_SYSTEM_TRAY_TRAY_CONSTANTS_H_
 #define ASH_COMMON_SYSTEM_TRAY_TRAY_CONSTANTS_H_
 
 #include "ash/ash_export.h"
 
 typedef unsigned int SkColor;
 
 namespace ash {
 
 extern const int kPaddingFromRightEdgeOfScreenBottomAlignment;
 extern const int kPaddingFromBottomOfScreenBottomAlignment;
 extern const int kPaddingFromOuterEdgeOfLauncherVerticalAlignment;
 extern const int kPaddingFromInnerEdgeOfLauncherVerticalAlignment;
 extern const int kPaddingFromBottomOfScreenVerticalAlignment;
 
 extern const int kBubblePaddingHorizontalBottom;
 extern const int kBubblePaddingHorizontalSide;
 extern const int kBubblePaddingVerticalBottom;
 extern const int kBubblePaddingVerticalSide;
 
-extern const int kPaddingFromEdgeOfShelf;
+extern const int kAdjustBackgroundPadding;
+
 extern const int kTrayBubbleAnchorTopInsetBottomAnchor;
 
 extern const int kTrayImageItemHorizontalPaddingBottomAlignment;
 extern const int kTrayImageItemHorizontalPaddingVerticalAlignment;
 extern const int kTrayImageItemVerticalPaddingVerticalAlignment;
 
 ASH_EXPORT extern const int kTrayItemSize;
 
 extern const int kTrayLabelItemHorizontalPaddingBottomAlignment;
 extern const int kTrayLabelItemVerticalPaddingVerticalAlignment;
@@ skipping 33 matching lines @@
 
 extern const int kTrayPopupMinWidth;
 extern const int kTrayPopupMaxWidth;
 extern const int kNotificationIconWidth;
 extern const int kNotificationButtonWidth;
 extern const int kTrayNotificationContentsWidth;
 
 extern const int kTrayAvatarCornerRadius;
 extern const int kTrayAvatarSize;
 
-extern const int kTraySpacing;
+extern const int kMessageCenterBubblePadding;
 extern const int kShelfItemHeight;
 
+// TODO(tdanderson): Update all button background to 32 by 32 in Chrome OS MD.
+// All tray background are sized 32 by 32 in Chrome OS MD.
+extern const int kShelfItemSizeMD;
+
+enum TrayConstant {
+  // Padding between items in the status tray area.
+  TRAY_SPACING,
+
+  // Padding between the edge of shelf and the item in status tray area.
+  TRAY_PADDING_FROM_EDGE_OF_SHELF,
+};
+
+int GetTrayConstant(TrayConstant constant);
+
 namespace test {
 const int kSettingsTrayItemViewId = 10000;
 const int kAccessibilityTrayItemViewId = 10001;
 }  // namespace test
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_TRAY_TRAY_CONSTANTS_H_