From bad38ac0f4d9b5b7ecc4105f609185a20b8be41f Mon Sep 17 00:00:00 2001
From: Wagner Maciel <wagnermaciel@google.com>
Date: Tue, 24 Sep 2024 17:42:34 -0400
Subject: [PATCH] refactor: create mixins for core classes

* This is an intermediary step so we can roll out calls
  to these empty mixins progressively.
* Once all of the instances of mat.core have been updated
  to also call mat.app-background and mat.elevation-classes
  we can move the styles over without breaking any clients
---
 src/dev-app/theme.scss        | 2 ++
 src/material/_index.scss      | 2 +-
 src/material/core/_core.scss  | 6 ++++++
 src/universal-app/styles.scss | 1 +
 4 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/dev-app/theme.scss b/src/dev-app/theme.scss
index 9a4eb8c6e9d3..908d228b948c 100644
--- a/src/dev-app/theme.scss
+++ b/src/dev-app/theme.scss
@@ -25,6 +25,8 @@ $candy-app-theme: mat.m2-define-light-theme((
 // have to load a single css file for Angular Material in your app.
 // **Be sure that you only ever include this mixin once!**
 @include mat.core();
+@include mat.app-background();
+@include mat.elevation-classes();
 
 // Include the default theme styles.
 @include mat.all-component-themes($candy-app-theme);
diff --git a/src/material/_index.scss b/src/material/_index.scss
index b00dcc5996e6..36f1d45b193a 100644
--- a/src/material/_index.scss
+++ b/src/material/_index.scss
@@ -36,7 +36,7 @@
 @forward './core/style/validation' as private-*;
 
 // Structural
-@forward './core/core' show core;
+@forward './core/core' show core, app-background, elevation-classes;
 @forward './core/ripple/ripple' show ripple;
 @forward './core/focus-indicators/private' show strong-focus-indicators,
   strong-focus-indicators-color, strong-focus-indicators-theme;
diff --git a/src/material/core/_core.scss b/src/material/core/_core.scss
index f0080ea547a8..34484bdac4c9 100644
--- a/src/material/core/_core.scss
+++ b/src/material/core/_core.scss
@@ -42,3 +42,9 @@
     }
   }
 }
+
+// Mixin that provides the .mat-app-background class.
+@mixin app-background() {}
+
+// Mixin that provides the .mat-elevation-* classes.
+@mixin elevation-classes() {}
diff --git a/src/universal-app/styles.scss b/src/universal-app/styles.scss
index 9e1af4470a0e..a043f31c880e 100644
--- a/src/universal-app/styles.scss
+++ b/src/universal-app/styles.scss
@@ -1,6 +1,7 @@
 @use '@angular/material' as mat;
 
 @include mat.core();
+@include mat.app-background();
 
 $theme: mat.define-theme((
   color: (