add onLoad prop to Image component (#2293)

# Summary

Closes #1442

We want to add new props to the Image Component.

## Test Plan

Added the Test component. 
Manually test that in Android and IOS platforms on new and old
Architectures.

### What are the steps to reproduce (after prerequisites)?

## Compatibility

| OS      | Implemented |
| ------- | :---------: |
| iOS     |    ✅     |
| Android |    ✅     |

android/src/main/java/com/horcrux/svg/ImageView.java

@@ -30,8 +30,12 @@ import com.facebook.react.bridge.Dynamic;
 import com.facebook.react.bridge.ReactContext;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.common.ReactConstants;
+import com.facebook.react.uimanager.UIManagerHelper;
+import com.facebook.react.uimanager.events.EventDispatcher;
 import com.facebook.react.views.imagehelper.ImageSource;
 import com.facebook.react.views.imagehelper.ResourceDrawableIdHelper;
+import com.horcrux.svg.events.SvgLoadEvent;
+
 import java.util.concurrent.atomic.AtomicBoolean;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
@@ -137,6 +141,15 @@ class ImageView extends RenderableView {
         new BaseBitmapDataSubscriber() {
           @Override
           public void onNewResultImpl(Bitmap bitmap) {
+            final EventDispatcher mEventDispatcher =
+            UIManagerHelper.getEventDispatcherForReactTag(mContext, getId());
+            mEventDispatcher.dispatchEvent(new SvgLoadEvent(
+                    UIManagerHelper.getSurfaceId(ImageView.this),
+                    getId(),
+                    mContext,
+                    uriString,
+                    bitmap.getWidth(),
+                    bitmap.getHeight()));
             mLoading.set(false);
             SvgView view = getSvgView();
             if (view != null) {

android/src/main/java/com/horcrux/svg/RenderableViewManager.java

@@ -82,6 +82,7 @@ import com.facebook.react.bridge.JavaOnlyMap;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.bridge.ReadableType;
+import com.facebook.react.common.MapBuilder;
 import com.facebook.react.uimanager.DisplayMetricsHolder;
 import com.facebook.react.uimanager.LayoutShadowNode;
 import com.facebook.react.uimanager.MatrixMathHelper;
@@ -134,7 +135,10 @@ import com.facebook.react.viewmanagers.RNSVGTextPathManagerDelegate;
 import com.facebook.react.viewmanagers.RNSVGTextPathManagerInterface;
 import com.facebook.react.viewmanagers.RNSVGUseManagerDelegate;
 import com.facebook.react.viewmanagers.RNSVGUseManagerInterface;
+import com.horcrux.svg.events.SvgLoadEvent;
+import java.util.HashMap;
 import java.util.Locale;
+import java.util.Map;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
@@ -926,6 +930,12 @@ class RenderableViewManager<T extends RenderableView> extends VirtualViewManager
     public void setMeetOrSlice(ImageView node, int meetOrSlice) {
       node.setMeetOrSlice(meetOrSlice);
     }
+
+    public Map<String, Object> getExportedCustomDirectEventTypeConstants() {
+      Map<String, Object> eventTypes = new HashMap<>();
+      eventTypes.put(SvgLoadEvent.EVENT_NAME, MapBuilder.of("registrationName", "onLoad"));
+      return eventTypes;
+    }
   }
 
   static class CircleViewManager extends RenderableViewManager<CircleView>

android/src/main/java/com/horcrux/svg/events/SvgLoadEvent.java

@@ -0,0 +1,47 @@
+package com.horcrux.svg.events;
+
+import com.facebook.react.bridge.Arguments;
+import com.facebook.react.bridge.ReactContext;
+import com.facebook.react.bridge.WritableMap;
+import com.facebook.react.uimanager.events.Event;
+import com.facebook.react.uimanager.events.RCTEventEmitter;
+import com.facebook.react.views.imagehelper.ImageSource;
+
+public class SvgLoadEvent extends Event<SvgLoadEvent> {
+
+  public static final String EVENT_NAME = "topLoad";
+  private final float width;
+  private final float height;
+  private final String uri;
+
+  public SvgLoadEvent(int surfaceId, int viewId, ReactContext mContext, String uriString, float width, float height) {
+    super(surfaceId, viewId);
+    ImageSource imageSource = new ImageSource(mContext, uriString);
+    this.uri = imageSource.getSource();;
+    this.width = width;
+    this.height = height;
+  }
+
+  @Override
+  public String getEventName() {
+    return EVENT_NAME;
+  }
+
+  @Override
+  public short getCoalescingKey() {
+    return 0;
+  }
+
+  @Override
+  public void dispatch(RCTEventEmitter rctEventEmitter) {
+    rctEventEmitter.receiveEvent(getViewTag(), getEventName(), getEventData());
+  }
+
+  protected WritableMap getEventData() {
+    WritableMap eventData = Arguments.createMap();
+    eventData.putDouble("width", width);
+    eventData.putDouble("height", height);
+    eventData.putString("uri", uri);
+    return eventData;
+  }
+}