Clean up some ash constants.

ash/shelf/overflow_button.cc

Index: ash/shelf/overflow_button.cc
diff --git a/ash/shelf/overflow_button.cc b/ash/shelf/overflow_button.cc
index e770232665c9db5bb7c171fdf229fc00176c0307..9f4a414cf79c7dc138240ab58b377e03e9ce5de1 100644
--- a/ash/shelf/overflow_button.cc
+++ b/ash/shelf/overflow_button.cc
@@ -171,7 +171,7 @@ gfx::Rect OverflowButton::CalculateButtonBounds() const {
   gfx::Rect content_bounds = GetContentsBounds();
   // Align the button to the top of a bottom-aligned shelf, to the right edge
   // a left-aligned shelf, and to the left edge of a right-aligned shelf.
-  const int inset = (GetShelfConstant(SHELF_SIZE) - kOverflowButtonSize) / 2;
+  const int inset = (kShelfSize - kOverflowButtonSize) / 2;
   const int x = alignment == SHELF_ALIGNMENT_LEFT
                     ? content_bounds.right() - inset - kOverflowButtonSize
                     : content_bounds.x() + inset;