Implement multi-source Images on iOS

Summary: Mirrors Android's support for multiple sources for Image, allowing us to fetch new images as the size of the view changes.

Reviewed By: mmmulani

Differential Revision: D3615134

fbshipit-source-id: 3d0bf2b75f63a4379e0e49f2dab9aea351b31d5f

Libraries/Image/ImageSourcePropType.js

@@ -13,44 +13,48 @@
 
 const PropTypes = require('react/lib/ReactPropTypes');
 
+const ImageURISourcePropType = PropTypes.shape({
+  /**
+   * `uri` is a string representing the resource identifier for the image, which
+   * could be an http address, a local file path, or the name of a static image
+   * resource (which should be wrapped in the `require('./path/to/image.png')`
+   * function).
+   */
+  uri: PropTypes.string,
+  /**
+   * `method` is the HTTP Method to use. Defaults to GET if not specified.
+   */
+  method: PropTypes.string,
+  /**
+   * `headers` is an object representing the HTTP headers to send along with the
+   * request for a remote image.
+   */
+  headers: PropTypes.objectOf(PropTypes.string),
+  /**
+   * `body` is the HTTP body to send with the request. This must be a valid
+   * UTF-8 string, and will be sent exactly as specified, with no
+   * additional encoding (e.g. URL-escaping or base64) applied.
+   */
+  body: PropTypes.string,
+  /**
+   * `width` and `height` can be specified if known at build time, in which case
+   * these will be used to set the default `<Image/>` component dimensions.
+   */
+  width: PropTypes.number,
+  height: PropTypes.number,
+  /**
+   * `scale` is used to indicate the scale factor of the image. Defaults to 1.0 if
+   * unspecified, meaning that one image pixel equates to one display point / DIP.
+   */
+  scale: PropTypes.number,
+});
+
 const ImageSourcePropType = PropTypes.oneOfType([
-  PropTypes.shape({
-    /**
-     * `uri` is a string representing the resource identifier for the image, which
-     * could be an http address, a local file path, or the name of a static image
-     * resource (which should be wrapped in the `require('./path/to/image.png')`
-     * function).
-     */
-    uri: PropTypes.string,
-    /**
-     * `method` is the HTTP Method to use. Defaults to GET if not specified.
-     */
-    method: PropTypes.string,
-    /**
-     * `headers` is an object representing the HTTP headers to send along with the
-     * request for a remote image.
-     */
-    headers: PropTypes.objectOf(PropTypes.string),
-    /**
-     * `body` is the HTTP body to send with the request. This must be a valid
-     * UTF-8 string, and will be sent exactly as specified, with no
-     * additional encoding (e.g. URL-escaping or base64) applied.
-     */
-    body: PropTypes.string,
-    /**
-     * `width` and `height` can be specified if known at build time, in which case
-     * these will be used to set the default `<Image/>` component dimensions.
-     */
-    width: PropTypes.number,
-    height: PropTypes.number,
-    /**
-     * `scale` is used to indicate the scale factor of the image. Defaults to 1.0 if
-     * unspecified, meaning that one image pixel equates to one display point / DIP.
-     */
-    scale: PropTypes.number,
-  }),
+  ImageURISourcePropType,
   // Opaque type returned by require('./image.jpg')
   PropTypes.number,
+  // Multiple sources
+  PropTypes.arrayOf(ImageURISourcePropType),
 ]);
 
 module.exports = ImageSourcePropType;