Button: support icon only buttons

This CL fixes padding for icon only buttons and horizontal
centering along with the width for the button so that the
parent can be resized.

Screenshot: https://i.imgur.com/Kfij3c0.png
Bug: none
Change-Id: I86137cbbf33d4b389f87dc66f9a903edc785ec48
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3192852
Commit-Queue: Alex Rudenko <[email protected]>
Reviewed-by: Jack Franklin <[email protected]>
diff --git a/front_end/ui/components/buttons/button.css b/front_end/ui/components/buttons/button.css
index ac08556..fe627b1 100644
--- a/front_end/ui/components/buttons/button.css
+++ b/front_end/ui/components/buttons/button.css
@@ -24,6 +24,8 @@
   height: 25px;
   line-height: 14px;
   padding: 5px 12px;
+  justify-content: center;
+  width: 100%;
 }
 
 button:focus-visible {
@@ -69,10 +71,14 @@
   border: 1px solid var(--color-background);
 }
 
-button.with-icon {
+button.text-with-icon {
   padding: 0 12px 0 4px;
 }
 
+button.only-icon {
+  padding: 0;
+}
+
 button devtools-icon {
   width: 19px;
   height: 19px;