Implemented inline image support for <Text>

Summary: @​public

This diff implements inline image support for <Text> nodes. Images are specified using <Image> tags, however all properties of the image are currently ignored apart from the source (including width/height styles).

Images are loaded asyncronously, and will trigger a text re-layout when they have loaded.

Reviewed By: @javache

Differential Revision: D2507725

fb-gh-sync-id: 59d0696d00a1bc531915cc35242a16b2dec96e85

Libraries/Image/RCTShadowVirtualImage.h

@@ -0,0 +1,25 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "RCTShadowView.h"
+#import "RCTImageComponent.h"
+
+@class RCTBridge;
+
+/**
+ * Shadow image component, used for embedding images in non-view contexts such
+ * as text. This is NOT used for ordinary <Image> views.
+ */
+@interface RCTShadowVirtualImage : RCTShadowView <RCTImageComponent>
+
+- (instancetype)initWithBridge:(RCTBridge *)bridge;
+
+@property (nonatomic, copy) NSDictionary *source;
+
+@end