Fix the absence of padding on some UI buttons.

chrome/browser/ui/views/harmony/layout_delegate.h

Index: chrome/browser/ui/views/harmony/layout_delegate.h
diff --git a/chrome/browser/ui/views/harmony/layout_delegate.h b/chrome/browser/ui/views/harmony/layout_delegate.h
index 4f39146e0e803a2daf736d7a15ed0d0076d6226d..9841b67c9e3f24dfff94c554e74ac90936bda2eb 100644
--- a/chrome/browser/ui/views/harmony/layout_delegate.h
+++ b/chrome/browser/ui/views/harmony/layout_delegate.h
@@ -12,6 +12,8 @@ class LayoutDelegate {
   enum class Metric {
     // Padding on the left and right side of a button's label.
     BUTTON_HORIZONTAL_PADDING,
+    // Default minimum width of a button.
+    BUTTON_MINIMUM_WIDTH,
     // Margin between the edge of a dialog and the left, right, or bottom of a
     // contained button.
     DIALOG_BUTTON_MARGIN,