refactor(material/theming): remove underscores from non-mdc density mixins (#20915)

For some components that don't have a corresponding implementation
in MDC Web, we added density mixins. We prefixed this with an
underscore to prevent premature use. Now we remove the underscore
as we're starting rollout in Google.

Author: jelbourn

.ng-dev/commit-message.ts

@@ -104,6 +104,7 @@ export const commitMessage: CommitMessageConfig = {
     'material/table',
     'material/tabs',
     'material/testing',
+    'material/theming',
     'material/toolbar',
     'material/tooltip',
     'material/tree',

src/material-experimental/mdc-paginator/_paginator-theme.scss

@@ -53,7 +53,7 @@
   }
 }
 
-@mixin _mat-mdc-paginator-density($config-or-theme) {
+@mixin mat-mdc-paginator-density($config-or-theme) {
   $density-scale: mat-get-density-config($config-or-theme);
   $height: _mat-density-prop-value($mat-paginator-density-config, $density-scale, height);
 
@@ -75,7 +75,7 @@
       @include mat-mdc-paginator-color($color);
     }
     @if $density != null {
-      @include _mat-mdc-paginator-density($density);
+      @include mat-mdc-paginator-density($density);
     }
     @if $typography != null {
       @include mat-mdc-paginator-typography($typography);

src/material/expansion/_expansion-theme.scss

@@ -74,7 +74,7 @@
   }
 }
 
-@mixin _mat-expansion-panel-density($config-or-theme) {
+@mixin mat-expansion-panel-density($config-or-theme) {
   $density-scale: mat-get-density-config($config-or-theme);
   $expanded-height: _mat-density-prop-value(
         $mat-expansion-panel-header-density-config, $density-scale, expanded-height);
@@ -103,7 +103,7 @@
       @include mat-expansion-panel-color($color);
     }
     @if $density != null {
-      @include _mat-expansion-panel-density($density);
+      @include mat-expansion-panel-density($density);
     }
     @if $typography != null {
       @include mat-expansion-panel-typography($typography);

src/material/stepper/_stepper-theme.scss

@@ -134,7 +134,7 @@
   }
 }
 
-@mixin _mat-stepper-density($config-or-theme) {
+@mixin mat-stepper-density($config-or-theme) {
   $density-scale: mat-get-density-config($config-or-theme);
   $height: _mat-density-prop-value($mat-stepper-density-config, $density-scale, height);
   $vertical-padding: ($height - $mat-stepper-label-header-height) / 2;
@@ -181,7 +181,7 @@
       @include mat-stepper-color($color);
     }
     @if $density != null {
-      @include _mat-stepper-density($density);
+      @include mat-stepper-density($density);
     }
     @if $typography != null {
       @include mat-stepper-typography($typography);

src/material/toolbar/_toolbar-theme.scss

@@ -82,7 +82,7 @@
   }
 }
 
-@mixin _mat-toolbar-density($config-or-theme) {
+@mixin mat-toolbar-density($config-or-theme) {
   $density-scale: mat-get-density-config($config-or-theme);
   $height-desktop: _mat-density-prop-value(
       $mat-toolbar-desktop-density-config, $density-scale, height);
@@ -113,7 +113,7 @@
       @include mat-toolbar-color($color);
     }
     @if $density != null {
-      @include _mat-toolbar-density($density);
+      @include mat-toolbar-density($density);
     }
     @if $typography != null {
       @include mat-toolbar-typography($typography);

src/material/tree/_tree-theme.scss

@@ -33,7 +33,7 @@
   }
 }
 
-@mixin _mat-tree-density($config-or-theme) {
+@mixin mat-tree-density($config-or-theme) {
   $density-scale: mat-get-density-config($config-or-theme);
   $height: _mat-density-prop-value($mat-tree-density-config, $density-scale, height);
 
@@ -55,7 +55,7 @@
       @include mat-tree-color($color);
     }
     @if $density != null {
-      @include _mat-tree-density($density);
+      @include mat-tree-density($density);
     }
     @if $typography != null {
       @include mat-tree-typography($typography);