StaticRenderer: Removed prop types (facebook#21348)

Summary:
related facebook#21342

 The `render` function, I was not able to specifically type since the props passed to it may vary. At the moment only `renderRow` function from ListView component is using StaticRenderer, and the type of the renderRow function is `Function`.
Let me know what your thoughts are on this. Thank you
Pull Request resolved: facebook#21348

Differential Revision: D10084990

Pulled By: TheSavior

fbshipit-source-id: a87a8d4976c6ffaf83dc0fddc758869dbc2e2803

Author: richardcann

Libraries/Components/StaticRenderer.js

@@ -12,18 +12,20 @@
 
 const React = require('React');
 
-const PropTypes = require('prop-types');
-
-class StaticRenderer extends React.Component<{
+type Props = $ReadOnly<{|
+  /**
+   * Indicates whether the render function needs to be called again
+   */
   shouldUpdate: boolean,
-  render: Function,
-}> {
-  static propTypes = {
-    shouldUpdate: PropTypes.bool.isRequired,
-    render: PropTypes.func.isRequired,
-  };
+  /**
+   * () => renderable
+   * A function that returns a renderable component
+   */
+  render: () => React.Node,
+|}>;
 
-  shouldComponentUpdate(nextProps: {shouldUpdate: boolean}): boolean {
+class StaticRenderer extends React.Component<Props> {
+  shouldComponentUpdate(nextProps: Props): boolean {
     return nextProps.shouldUpdate;
   }