mac: New asset for the tabstrip border, tweak drawing.

chrome/browser/ui/cocoa/image_button_cell.mm

Index: chrome/browser/ui/cocoa/image_button_cell.mm
diff --git a/chrome/browser/ui/cocoa/image_button_cell.mm b/chrome/browser/ui/cocoa/image_button_cell.mm
index 5457908483efabc93baa352b31639fa42b754860..4a532be449dd3bfe806d89fa73533dd79948f32c 100644
--- a/chrome/browser/ui/cocoa/image_button_cell.mm
+++ b/chrome/browser/ui/cocoa/image_button_cell.mm
@@ -10,8 +10,6 @@
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/image/image.h"
 
-namespace {
-
 // Adjust the overlay position relative to the top right of the button image.
 const CGFloat kOverlayOffsetX = -3;
 const CGFloat kOverlayOffsetY = 5;
@@ -20,8 +18,6 @@ const CGFloat kOverlayOffsetY = 5;
 // slightly lighter color. We do this by just reducing the alpha.
 const CGFloat kImageNoFocusAlpha = 0.65;
 
-} // namespace
-
 @interface ImageButtonCell (Private)
 - (void)sharedInit;
 - (image_button_cell::ButtonState)currentButtonState;