Update shelf spacing in Chrome OS according to the MD specs

ash/shelf/shelf_constants.h

Index: ash/shelf/shelf_constants.h
diff --git a/ash/shelf/shelf_constants.h b/ash/shelf/shelf_constants.h
index d7f0825b7394263afdec8f6f8952ef8c6e7f7a03..5c5e3a9f74d287610ffd7296fadbd5842d3e94b8 100644
--- a/ash/shelf/shelf_constants.h
+++ b/ash/shelf/shelf_constants.h
@@ -9,19 +9,39 @@
 
 namespace ash {
 
+enum ShelfLayoutConstant {
+  // 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
+};
+
+ASH_EXPORT int GetShelfLayoutConstant(ShelfLayoutConstant constant);
+
 // Invalid image resource id used for ShelfItemDetails.
 extern const int kInvalidImageResourceID;
 
-const int kInvalidShelfID = 0;
+// 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;
 
-// Size of the shelf when visible (height when the shelf is horizontal).
-ASH_EXPORT extern const int kShelfSize;
+// 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 space between buttons on the shelf.
-ASH_EXPORT extern const int kShelfButtonSpacing;
+// Size of the shelf when auto-hidden.
+ASH_EXPORT extern const int kAutoHideSize;

[bruthig, 2016/06/03 20:18:17]

|kAutoHideSize| is too general of a variable name to be in the ash namespace
scope.  You could add it to a class or at least make the name more specific.
i.e. kShelfAutoHideSize.  My preference is the former.

[yiyix, 2016/06/10 19:26:04]

This constant is used in both shelf_layout_manager class and
ash_popup_alignment_delegate class. I update the name to kShelfAutoHideSize to
make it more specific.

 
-// Size allocated for each button on the shelf.
-ASH_EXPORT extern const int kShelfButtonSize;
+// 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;
 
 // The direction of the focus cycling.
 enum CycleDirection {