introduce RCTViewUtils

Summary:
Changelog: [Internal]

in this diff, i convert the following method to a C function.
https://www.internalfb.com/code/fbsource/[c58818169205f1e0fa816968efdb4c3fac8333e9]/xplat/js/react-native-github/React/Views/RCTView.h?lines=43

besides for testing demonstration purposes later in the stack, C functions are a superior choice to static class methods because they incur less binary size cost (see section 4.3 of https://swolchok.github.io/objcperf/ if you're curious, and https://fb.workplace.com/groups/aexpixfn/posts/1909150855887748 for the impact of a conversion)

Reviewed By: RSNara

Differential Revision: D31949241

fbshipit-source-id: dd40871d48f1de168d360168c4dd60015145d7e3

BUCK

@@ -307,6 +307,7 @@ REACT_PUBLIC_HEADERS = {
     "React/RCTVersion.h": RCTBASE_PATH + "RCTVersion.h",
     "React/RCTView.h": RCTVIEWS_PATH + "RCTView.h",
     "React/RCTViewManager.h": RCTVIEWS_PATH + "RCTViewManager.h",
+    "React/RCTViewUtils.h": RCTVIEWS_PATH + "RCTViewUtils.h",
     "React/RCTWeakProxy.h": RCTBASE_PATH + "RCTWeakProxy.h",
     "React/RCTWeakViewHolder.h": RCTVIEWS_PATH + "RCTWeakViewHolder.h",
     "React/RCTWrapperViewController.h": RCTVIEWS_PATH + "RCTWrapperViewController.h",

React/Views/RCTViewUtils.h

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import <React/RCTDefines.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+RCT_EXTERN_C_BEGIN
+
+UIEdgeInsets RCTContentInsets(UIView *view);
+
+RCT_EXTERN_C_END
+
+NS_ASSUME_NONNULL_END

React/Views/RCTViewUtils.m

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import "RCTViewUtils.h"
+
+#import "UIView+React.h"
+
+UIEdgeInsets RCTContentInsets(UIView *view)
+{
+  while (view) {
+    UIViewController *controller = view.reactViewController;
+    if (controller) {
+      return controller.view.safeAreaInsets;
+    }
+    view = view.superview;
+  }
+  return UIEdgeInsetsZero;
+}

packages/rn-tester/Podfile.lock

@@ -881,7 +881,7 @@ SPEC CHECKSUMS:
   CocoaAsyncSocket: 065fd1e645c7abab64f7a6a2007a48038fdc6a99
   DoubleConversion: 831926d9b8bf8166fd87886c4abab286c2422662
   FBLazyVector: b81a2b70c72d8b0aefb652cea22c11e9ffd02949
-  FBReactNativeSpec: c41af89a2aca37e9fe937133ffe6758301ded893
+  FBReactNativeSpec: cd36c48651d54982428c1b0afd5557993b45e92c
   Flipper: 30e8eeeed6abdc98edaf32af0cda2f198be4b733
   Flipper-Boost-iOSX: fd1e2b8cbef7e662a122412d7ac5f5bea715403c
   Flipper-DoubleConversion: 57ffbe81ef95306cc9e69c4aa3aeeeeb58a6a28c
@@ -923,10 +923,10 @@ SPEC CHECKSUMS:
   React-RCTTest: 12bbd7fc2e72bd9920dc7286c5b8ef96639582b6
   React-RCTText: e9146b2c0550a83d1335bfe2553760070a2d75c7
   React-RCTVibration: 50be9c390f2da76045ef0dfdefa18b9cf9f35cfa
-  React-rncore: a1249129f80f05d7e3bcba35239ceb394c1052cc
+  React-rncore: fb776508453c32c72c6325f421468eb8a1f3e2c4
   React-runtimeexecutor: 4b0c6eb341c7d3ceb5e2385cb0fdb9bf701024f3
   ReactCommon: 7a2714d1128f965392b6f99a8b390e3aa38c9569
-  ScreenshotManager: ec701affd6d2a5dabf8739b0cdcc937f7dbd2ac6
+  ScreenshotManager: b6b23f4913712a245102024854656634fee33265
   Yoga: c0d06f5380d34e939f55420669a60fe08b79bd75
   YogaKit: f782866e155069a2cca2517aafea43200b01fd5a