[admob][android] Add custom Banner component wrapper

lib/modules/admob/Banner.js

@@ -1,11 +1,58 @@
-import { PropTypes } from 'react';
+import React, { PropTypes } from 'react';
 import { requireNativeComponent, View } from 'react-native';
 
-const Banner = {
-  name: 'Banner',
-  propTypes: {
-    src: PropTypes.string,
-  },
-};
+class Banner extends React.Component {
 
-module.exports = requireNativeComponent('RNFirebaseAdMobBanner', Banner);
+  static propTypes = {
+    ...View.propTypes,
+    size: PropTypes.string,
+    unitId: PropTypes.string,
+    onAdLoaded: PropTypes.func,
+  };
+
+  static defaultProps = {
+    size: 'SMART_BANNER',
+    unitId: 'ca-app-pub-3940256099942544/6300978111', // Testing
+  };
+
+  constructor() {
+    super();
+    this.state = {
+      width: 0,
+      height: 0,
+    };
+  }
+
+  onBannerEvent = ({ nativeEvent }) => {
+    if (this.props[nativeEvent.type]) {
+      if (nativeEvent.type === 'onAdFailedToLoad') {
+        const error = new Error(nativeEvent.payload.message);
+        error.code = nativeEvent.payload.code;
+        this.props[nativeEvent.type](error);
+      } else {
+        this.props[nativeEvent.type](nativeEvent.payload || {});
+      }
+    }
+
+    if (nativeEvent.type === 'onSizeChange') this.updateSize(nativeEvent.payload);
+  };
+
+  updateSize = ({ width, height }) => {
+    this.setState({ width, height });
+  };
+
+  render() {
+    return (
+      <RNFirebaseAdMobBanner
+        {...this.props}
+        style={[this.props.style, { ...this.state }]}
+        bannerEvent={this.onBannerEvent}
+      />
+    );
+  }
+
+}
+
+const RNFirebaseAdMobBanner = requireNativeComponent('RNFirebaseAdMobBanner', Banner);
+
+export default Banner;