Introducing <ImageBackground>, replacement for <Image> which supports nesting views

Summary:
We are removing support of nesting views inside <Image> component. We decided to do this because having this feature makes supporting `intrinsinc content size` of the `<Image>` impossible; so when the transition process is complete, there will be no need to specify image size explicitly, it can be inferred from actual image bitmap.

And this is the step #0.

<ImageBackground> is very simple drop-in replacement which implements this functionality via very simple styling.
Please, use <ImageBackground> instead of <Image> if you want to put something inside.

Reviewed By: yungsters

Differential Revision: D5100021

fbshipit-source-id: 640c0fb2d1066e166d974efba39b4cfaaee7dd45

RNTester/js/ImageExample.js

@@ -20,6 +20,7 @@ var {
   StyleSheet,
   Text,
   View,
+  ImageBackground,
 } = ReactNative;
 
 var base64Icon = 'data:image/png;base64,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';
@@ -117,7 +118,7 @@ var NetworkImageExample = React.createClass({
       </View> : null;
     return this.state.error ?
       <Text>{this.state.error}</Text> :
-      <Image
+      <ImageBackground
         source={this.props.source}
         style={[styles.base, {overflow: 'visible'}]}
         onLoadStart={(e) => this.setState({loading: true})}
@@ -125,7 +126,7 @@ var NetworkImageExample = React.createClass({
         onProgress={(e) => this.setState({progress: Math.round(100 * e.nativeEvent.loaded / e.nativeEvent.total)})}
         onLoad={() => this.setState({loading: false, error: false})}>
         {loader}
-      </Image>;
+      </ImageBackground>;
   }
 });
 
@@ -436,13 +437,13 @@ exports.examples = [
     title: 'Nesting',
     render: function() {
       return (
-        <Image
+        <ImageBackground
           style={{width: 60, height: 60, backgroundColor: 'transparent'}}
           source={fullImage}>
           <Text style={styles.nestedText}>
             React
           </Text>
-        </Image>
+        </ImageBackground>
       );
     },
   },