Position close buttons in bubbles based on a layout delegate constant.

chrome/browser/ui/views/harmony/harmony_layout_delegate.cc

Index: chrome/browser/ui/views/harmony/harmony_layout_delegate.cc
diff --git a/chrome/browser/ui/views/harmony/harmony_layout_delegate.cc b/chrome/browser/ui/views/harmony/harmony_layout_delegate.cc
index c833ef37f23fbc48a9257d1f27cb5ec8336ebe60..fa3f7ce43dbc7a5eff6cb71c95a54eaf9cd7e960 100644
--- a/chrome/browser/ui/views/harmony/harmony_layout_delegate.cc
+++ b/chrome/browser/ui/views/harmony/harmony_layout_delegate.cc
@@ -19,6 +19,10 @@ int HarmonyLayoutDelegate::GetMetric(Metric metric) const {
   switch (metric) {
     case Metric::DIALOG_BUTTON_MARGIN:
       return kHarmonyLayoutUnit;
+    case Metric::DIALOG_CLOSE_BUTTON_MARGIN:
+      // TODO(pkasting): The "- 4" here is a hack that matches the extra padding
+      // in vector_icon_button.cc and should be removed when that padding is.
+      return (kHarmonyLayoutUnit / 2) - 4;
     case Metric::PANEL_CONTENT_MARGIN:
       return kHarmonyLayoutUnit;
     case Metric::RELATED_BUTTON_HORIZONTAL_SPACING: