Button icons aria labels changes #14998 (#15112)

* Button icons aria labels changes #14998

* Button icons aria labels changes Fixes #14998

Author: Suresh918

src/material-examples/button-types/button-types-example.html

@@ -40,20 +40,20 @@ <h3>Flat Buttons</h3>
 
 <h3>Icon Buttons</h3>
 <div class="example-button-row">
-  <button mat-icon-button>
-    <mat-icon aria-label="Example icon-button with a heart icon">favorite</mat-icon>
+  <button mat-icon-button aria-label="Example icon-button with a heart icon">
+    <mat-icon>favorite</mat-icon>
   </button>
-  <button mat-icon-button color="primary">
-    <mat-icon aria-label="Example icon-button with a heart icon">favorite</mat-icon>
+  <button mat-icon-button color="primary" aria-label="Example icon-button with a heart icon">
+    <mat-icon>favorite</mat-icon>
   </button>
-  <button mat-icon-button color="accent">
-    <mat-icon aria-label="Example icon-button with a heart icon">favorite</mat-icon>
+  <button mat-icon-button color="accent" aria-label="Example icon-button with a heart icon">
+    <mat-icon>favorite</mat-icon>
   </button>
-  <button mat-icon-button color="warn">
-    <mat-icon aria-label="Example icon-button with a heart icon">favorite</mat-icon>
+  <button mat-icon-button color="warn" aria-label="Example icon-button with a heart icon">
+    <mat-icon>favorite</mat-icon>
   </button>
-  <button mat-icon-button disabled>
-    <mat-icon aria-label="Example icon-button with a heart icon">favorite</mat-icon>
+  <button mat-icon-button disabled aria-label="Example icon-button with a heart icon">
+    <mat-icon>favorite</mat-icon>
   </button>
 </div>
 
@@ -64,8 +64,8 @@ <h3>Fab Buttons</h3>
   <button mat-fab color="accent">Accent</button>
   <button mat-fab color="warn">Warn</button>
   <button mat-fab disabled>Disabled</button>
-  <button mat-fab>
-    <mat-icon aria-label="Example icon-button with a heart icon">favorite</mat-icon>
+  <button mat-fab aria-label="Example icon-button with a heart icon">
+    <mat-icon>favorite</mat-icon>
   </button>
   <a mat-fab routerLink=".">Link</a>
 </div>
@@ -77,8 +77,8 @@ <h3>Mini Fab Buttons</h3>
   <button mat-mini-fab color="accent">Accent</button>
   <button mat-mini-fab color="warn">Warn</button>
   <button mat-mini-fab disabled>Disabled</button>
-  <button mat-mini-fab>
-    <mat-icon aria-label="Example icon-button with a heart icon">favorite</mat-icon>
+  <button mat-mini-fab aria-label="Example icon-button with a heart icon">
+    <mat-icon>favorite</mat-icon>
   </button>
   <a mat-mini-fab routerLink=".">Link</a>
 </div>