Add VectorIconButton functionality to ImageButton.

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 dafc261f717777a03534868371bec9eabd4890e1..593a5dfdb6353f6a3c0bed3f20bf10d5b253e986 100644
--- a/chrome/browser/ui/views/harmony/harmony_layout_delegate.cc
+++ b/chrome/browser/ui/views/harmony/harmony_layout_delegate.cc
@@ -19,6 +19,8 @@ int HarmonyLayoutDelegate::GetMetric(Metric metric) const {
   switch (metric) {
     case Metric::BUTTON_HORIZONTAL_PADDING:
       return kHarmonyLayoutUnit;
+    case Metric::BUTTON_MARGIN:
+      return 0;
     case Metric::DIALOG_BUTTON_MARGIN:
       return kHarmonyLayoutUnit;
     case Metric::BUTTON_MAX_LINKABLE_WIDTH:
@@ -31,9 +33,7 @@ int HarmonyLayoutDelegate::GetMetric(Metric metric) const {
     case Metric::DIALOG_BUTTON_TOP_SPACING:
       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;
+      return kHarmonyLayoutUnit / 2;
     case Metric::PANEL_CONTENT_MARGIN:
       return kHarmonyLayoutUnit;
     case Metric::RELATED_BUTTON_HORIZONTAL_SPACING: