[libadwaita/wip/exalm/menu-image-button] stylesheet: Support .image-button on menu buttons

[Alexander Mikhaylenko <alexm src gnome org>]

commit 471d82670ff1a8fad16d08d1f01a95b0ad99974c
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Fri Sep 10 20:16:31 2021 +0500

    stylesheet: Support .image-button on menu buttons
    
    Fixes https://gitlab.gnome.org/GNOME/libadwaita/-/issues/266

 src/stylesheet/widgets/_buttons.scss  |  6 ++++++
 src/stylesheet/widgets/_toolbars.scss | 12 ++++++++++++
 2 files changed, 18 insertions(+)
---
diff --git a/src/stylesheet/widgets/_buttons.scss b/src/stylesheet/widgets/_buttons.scss
index d68c73ac..823990d4 100644
--- a/src/stylesheet/widgets/_buttons.scss
+++ b/src/stylesheet/widgets/_buttons.scss
@@ -371,6 +371,12 @@ menubutton {
   &.flat > button { @extend %button_basic_flat; }
   &.outline > button { @extend %outline_button; }
 
+  &.image-button > button {
+    min-width: 24px;
+    padding-left: 5px;
+    padding-right: 5px;
+  }
+
   arrow {
     min-height: 16px;
     min-width: 16px;
diff --git a/src/stylesheet/widgets/_toolbars.scss b/src/stylesheet/widgets/_toolbars.scss
index f308dd03..c47aaca0 100644
--- a/src/stylesheet/widgets/_toolbars.scss
+++ b/src/stylesheet/widgets/_toolbars.scss
@@ -7,6 +7,12 @@
     }
   }
 
+  menubutton:not(.raised):not(.suggested-action):not(.destructive-action) {
+    &.image-button > button {
+      @extend %button_basic_flat;
+    }
+  }
+
   .linked button:not(.raised):not(.suggested-action):not(.destructive-action) {
     &.arrow-button,
     &.image-button,
@@ -70,6 +76,12 @@
       }
     }
 
+    menubutton:not(.raised):not(.suggested-action):not(.destructive-action) {
+      &.image-button > button {
+        @extend %button_basic_raised;
+      }
+    }
+
     entry,
     spinbutton,
     splitbutton,