[Mac][Material Design] Fix indentation of first and last bookmark items.

chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.mm

Index: chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.mm
diff --git a/chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.mm b/chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.mm
index 44b2343b9a3b99e0b0d00757ddc1e76fa8bac6fb..530d2b0f7e4286c38958d5ce6dca7a5279cbcd53 100644
--- a/chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.mm
+++ b/chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.mm
@@ -269,14 +269,14 @@ CGFloat BookmarkLeftMargin() {
   if (!ui::MaterialDesignController::IsModeMaterial()) {
     return 2.0;
   }
-  return 12.0;
+  return 8.0;
 }
 
 CGFloat BookmarkRightMargin() {
   if (!ui::MaterialDesignController::IsModeMaterial()) {
     return 2.0;
   }
-  return 12.0;
+  return 8.0;
 }
 
 }  // namespace bookmarks