Add ability for Animated views to be created with scale X or scale Y

Summary:
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*Accidentally closed previous PR*

Sometimes it can be useful to have an animated view be created with either scale X or scale Y in cases where scaleXY might not be as visually appealing.

Test Plan
Tested on both ios and android in the sample project:

https://github.com/Liamandrew/ScaleAnimationSample

![scaleanimation](https://user-images.githubusercontent.com/30114733/37023697-d0aa7372-217a-11e8-8d3b-2958c63ad83a.gif)
Closes facebook#18220

Differential Revision: D7542334

Pulled By: hramos

fbshipit-source-id: 208472e5d8f5a04ca3c3a99adce77b035e331ef1

Author: Liamandrew

Libraries/LayoutAnimation/LayoutAnimation.js

@@ -32,6 +32,8 @@ const Types = keyMirror(TypesEnum);
 
 const PropertiesEnum = {
   opacity: true,
+  scaleX: true,
+  scaleY: true,
   scaleXY: true,
 };
 const Properties = keyMirror(PropertiesEnum);

React/Modules/RCTUIManager.m

@@ -595,6 +595,10 @@ - (RCTViewManagerUIBlock)uiBlockWithLayoutUpdateForRootView:(RCTRootShadowView *
         NSString *property = creatingLayoutAnimation.property;
         if ([property isEqualToString:@"scaleXY"]) {
           view.layer.transform = CATransform3DMakeScale(0, 0, 0);
+        } else if ([property isEqualToString:@"scaleX"]) {
+        view.layer.transform = CATransform3DMakeScale(0, 1, 0);
+        } else if ([property isEqualToString:@"scaleY"]) {
+        view.layer.transform = CATransform3DMakeScale(1, 0, 0);
         } else if ([property isEqualToString:@"opacity"]) {
           view.layer.opacity = 0.0;
         } else {
@@ -603,7 +607,11 @@ - (RCTViewManagerUIBlock)uiBlockWithLayoutUpdateForRootView:(RCTRootShadowView *
         }
 
         [creatingLayoutAnimation performAnimations:^{
-          if ([property isEqualToString:@"scaleXY"]) {
+          if (
+            [property isEqualToString:@"scaleX"] ||
+            [property isEqualToString:@"scaleY"] ||
+            [property isEqualToString:@"scaleXY"]
+          ) {
             view.layer.transform = finalTransform;
           } else if ([property isEqualToString:@"opacity"]) {
             view.layer.opacity = finalOpacity;
@@ -738,6 +746,10 @@ - (void)_removeChildren:(NSArray<UIView *> *)children
     [deletingLayoutAnimation performAnimations:^{
       if ([property isEqualToString:@"scaleXY"]) {
         removedChild.layer.transform = CATransform3DMakeScale(0.001, 0.001, 0.001);
+      } else if ([property isEqualToString:@"scaleX"]) {
+      removedChild.layer.transform = CATransform3DMakeScale(0.001, 1, 0.001);
+      } else if ([property isEqualToString:@"scaleY"]) {
+      removedChild.layer.transform = CATransform3DMakeScale(1, 0.001, 0.001);
       } else if ([property isEqualToString:@"opacity"]) {
         removedChild.layer.opacity = 0.0;
       } else {

ReactAndroid/src/main/java/com/facebook/react/uimanager/layoutanimation/AnimatedPropertyType.java

@@ -8,6 +8,8 @@
  */
 /* package */ enum AnimatedPropertyType {
   OPACITY("opacity"),
+  SCALE_X("scaleX"),
+  SCALE_Y("scaleY"),
   SCALE_XY("scaleXY");
 
   private final String mName;

ReactAndroid/src/main/java/com/facebook/react/uimanager/layoutanimation/BaseLayoutAnimation.java

@@ -42,6 +42,32 @@ Animation createAnimationImpl(View view, int x, int y, int width, int height) {
               Animation.RELATIVE_TO_SELF,
               .5f);
         }
+        case SCALE_X: {
+          float fromValue = isReverse() ? 1.0f : 0.0f;
+          float toValue = isReverse() ? 0.0f : 1.0f;
+          return new ScaleAnimation(
+              fromValue,
+              toValue,
+              1f,
+              1f,
+              Animation.RELATIVE_TO_SELF,
+              .5f,
+              Animation.RELATIVE_TO_SELF,
+              0f);
+        }
+        case SCALE_Y: {
+          float fromValue = isReverse() ? 1.0f : 0.0f;
+          float toValue = isReverse() ? 0.0f : 1.0f;
+          return new ScaleAnimation(
+              1f,
+              1f,
+              fromValue,
+              toValue,
+              Animation.RELATIVE_TO_SELF,
+              0f,
+              Animation.RELATIVE_TO_SELF,
+              .5f);
+        }
         default:
           throw new IllegalViewOperationException(
               "Missing animation for property : " + mAnimatedProperty);