Fabric: RCTViewComponentView, storing just applied layoutMetrics

Summary:
This will be useful for this class and for subclasses soon.
For instance, when we draw something in `drawRect:`, we need to know exact content frame for rendering.

Reviewed By: mdvacca

Differential Revision: D7751855

fbshipit-source-id: 5d688368edd7b4f3c8c19d54ca701a9cc361270b

React/Fabric/Mounting/RCTViewComponentView.h

@@ -9,13 +9,17 @@
 
 #import <React/RCTComponentViewProtocol.h>
 #import <React/UIView+ComponentViewProtocol.h>
+#import <fabric/core/LayoutMetrics.h>
 
 NS_ASSUME_NONNULL_BEGIN
 
 /**
  * UIView class for <View> component.
  */
-@interface RCTViewComponentView : UIView <RCTComponentViewProtocol>
+@interface RCTViewComponentView : UIView <RCTComponentViewProtocol> {
+@protected
+  facebook::react::LayoutMetrics _layoutMetrics;
+}
 
 @end
 

React/Fabric/Mounting/RCTViewComponentView.mm

@@ -30,4 +30,12 @@ using namespace facebook::react;
   // TODO: Implement all sutable non-layout <View> props.
 }
 
+- (void)updateLayoutMetrics:(LayoutMetrics)layoutMetrics
+           oldLayoutMetrics:(LayoutMetrics)oldLayoutMetrics
+{
+  [super updateLayoutMetrics:layoutMetrics oldLayoutMetrics:oldLayoutMetrics];
+
+  _layoutMetrics = layoutMetrics;
+}
+
 @end