fix(material/button): remove concrete icon button theme styles

Author: andrewseguin

src/material/button/_icon-button-theme.scss

@@ -67,43 +67,12 @@
 }
 
 @mixin density($theme) {
+  $tokens: m2-icon-button.get-density-tokens($theme);
   @if inspection.get-theme-version($theme) == 1 {
-    @include token-utils.values(map.get(m3-icon-button.get-tokens($theme), density));
-  } @else {
-    $icon-size: 24px;
-    $density-scale: inspection.get-theme-density($theme);
-    $size-map: (
-      0: 48px,
-      -1: 44px,
-      -2: 40px,
-      -3: 36px,
-      -4: 32px,
-      -5: 28px,
-    );
-    $calculated-size: map.get($size-map, $density-scale);
-
-    @include token-utils.values(
-        m2-icon-button.get-density-tokens(
-            $theme, $exclude: (icon-button-state-layer-size))
-    );
-
-    // Use `mat-mdc-button-base` to increase the specificity over the button's structural styles.
-    .mat-mdc-icon-button.mat-mdc-button-base {
-      // Match the styles that used to be present. This is necessary for backwards
-      // compat to match the previous implementations selector count (two classes).
-      --mdc-icon-button-state-layer-size: #{$calculated-size};
-      --mat-icon-button-state-layer-size: #{$calculated-size};
-
-      // TODO: Switch calculated-size to "var(--mat-icon-button-state-layer-size)"
-      // Currently fails validation because the variable is "undefined"
-      // in the sass stack.
-      // TODO: Switch icon-size to "var(--mat-icon-button-icon-size)". Currently
-      // fails validation because the variable is "undefined" in the sass stack.
-      width: var(--mat-icon-button-state-layer-size);
-      height: var(--mat-icon-button-state-layer-size);
-      padding: math.div($calculated-size - $icon-size, 2);
-    }
+    $tokens: map.get(m3-icon-button.get-tokens($theme), density);
   }
+
+  @include token-utils.values($tokens);
 }
 
 /// Defines the tokens that will be available in the `overrides` mixin and for docs extraction.