Update shelf spacing in Chrome OS according to the MD specs

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"
 
 namespace ash {
 
 enum ShelfConstant {
   // The alpha value for the shelf background when a window is overlapping.
-  SHELF_BACKGROUND_ALPHA
+  SHELF_BACKGROUND_ALPHA,
+
+  // Size of the shelf when visible (height when the shelf is horizontal and
+  // width when the shelf is vertical).
+  SHELF_SIZE,
+
+  // Size of the space between buttons on the shelf.
+  SHELF_BUTTON_SPACING,
+
+  // Size allocated for each button on the shelf.
+  SHELF_BUTTON_SIZE
 };
 
 // Invalid image resource id used for ShelfItemDetails.
 extern const int kInvalidImageResourceID;
 
+// We reserve a small area on the edge of the workspace area to ensure that
+// the resize handle at the edge of the window can be hit.
+extern const int kWorkspaceAreaVisibleInset;
+
+// When autohidden we extend the touch hit target onto the screen so that the
+// user can drag the shelf out.
+extern const int kWorkspaceAreaAutoHideInset;
+
+// Size of the shelf when auto-hidden.
+ASH_EXPORT extern const int kShelfAutoHideSize;
+
+// Inset between the inner edge of the shelf (towards centre of screen), and
+// the shelf items, notifications, status area etc.
+extern const int kShelfItemInset;
+
 const int kInvalidShelfID = 0;
 
-// Size of the shelf when visible (height when the shelf is horizontal).
-ASH_EXPORT extern const int kShelfSize;
-
-// Size of the space between buttons on the shelf.
-ASH_EXPORT extern const int kShelfButtonSpacing;
-
-// 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_