Parametrize some more constants that will be changing in MD.

chrome/browser/ui/views/layout_constants.h

Index: chrome/browser/ui/views/layout_constants.h
diff --git a/chrome/browser/ui/views/layout_constants.h b/chrome/browser/ui/views/layout_constants.h
index 0125719c2b30458fd088da17b716e8e27273c9e0..14a629bfb6b3a42b1db3bc5fe7cc50e0b2cf554b 100644
--- a/chrome/browser/ui/views/layout_constants.h
+++ b/chrome/browser/ui/views/layout_constants.h
@@ -33,6 +33,9 @@ enum LayoutConstant {
   // The vertical padding of items in the location bar.
   LOCATION_BAR_VERTICAL_PADDING,
 
+  // The width of the New Tab button.
+  NEW_TAB_BUTTON_WIDTH,
+
   // The number of pixels in the omnibox dropdown border image interior to
   // the actual border.
   OMNIBOX_DROPDOWN_BORDER_INTERIOR,
@@ -40,6 +43,9 @@ enum LayoutConstant {
   // The font size to use in the location bar and omnibox dropdown, in pixels.
   OMNIBOX_FONT_PIXEL_SIZE,
 
+  // The amount of overlap between the last tab and the new tab button.
+  TABSTRIP_NEW_TAB_BUTTON_OVERLAP,
+
   // The amount of overlap between two adjacent tabs.
   TABSTRIP_TAB_OVERLAP,