update custom demo

components/icon/demo/custom.md

@@ -28,57 +28,9 @@ const AntDesignIcon = props => (
   <Icon component={AntDesignSvg} {...props} />
 );
 
-const SvgDefinitions = () => (
-  <svg className="svg-common-definitions">
-    <defs>
-      <linearGradient id="gradient-demo">
-        <stop offset="20%" stopColor="#39F" />
-        <stop offset="90%" stopColor="#F3F" />
-      </linearGradient>
-    </defs>
-  </svg>
-);
-
-const MaterialHomeIcon = props => (
-  <Icon viewBox="0 0 24 24" {...props}>
-    {/* you should pass SVG paths */}
-    <path d="M10 20v-6h4v6h5v-8h3L12 3 2 12h3v8z" />
-  </Icon>
-);
-
-const MaterialColorfulHomeIcon = props => (
-  <MaterialHomeIcon
-    {...props}
-    component={svgProps => (
-      <svg {...svgProps}>
-        <defs>
-          <linearGradient id="gradient">
-            <stop offset="30%" stopColor="#8360c3" />
-            <stop offset="70%" stopColor="#2ebf91" />
-          </linearGradient>
-        </defs>
-        {React.Children.map(
-            svgProps.children,
-            child => React.cloneElement(
-              child,
-              child.type === 'path' ? { fill: 'url(#gradient)' } : {}
-            )
-        )}
-      </svg>
-    )}
-  />
-);
-
 ReactDOM.render(
   <div className="custom-icons-list">
     <HeartIcon style={{ color: 'hotpink' }} />
-    <SvgDefinitions />
-    <HeartIcon
-      style={{ fontSize: '18px' }}
-      svgStyle={{ fill: 'url(#gradient-demo)' }}
-    />
-    <MaterialHomeIcon style={{ color: '#8360c3' }} />
-    <MaterialColorfulHomeIcon style={{ fontSize: '18px' }} />
     <AntDesignIcon style={{ fontSize: '32px' }} />
   </div>,
   mountNode
@@ -89,10 +41,4 @@ ReactDOM.render(
 .custom-icons-list > .anticon {
   margin-right: 6px;
 }
-
-.custom-icons-list > .svg-common-definitions {
-  position: absolute;
-  width: 0;
-  height: 0;
-}
 ```