add scrollTo metadata RCTBackedTextInputViewProtocol

Summary:
fixing oncall issue: https://fb.workplace.com/groups/rn.support/permalink/7241260632589156/

in this diff, we add the properties to the native views that are needed for the `onScroll` event.

`UITextField` is not a `UIScrollView` unlike `UITextView`, so we need to add these dummy properties

Changelog: [Internal]

Reviewed By: sammy-SC

Differential Revision: D32523147

fbshipit-source-id: 1d4f227f498fa1c333e2d6c457484b559ca18f7e

Author: philIip

Libraries/Text/TextInput/RCTBackedTextInputViewProtocol.h

@@ -31,6 +31,10 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic, assign) UITextFieldViewMode clearButtonMode;
 @property (nonatomic, getter=isScrollEnabled) BOOL scrollEnabled;
 @property (nonatomic, strong, nullable) NSString *inputAccessoryViewID;
+@property (nonatomic, assign, readonly) CGFloat zoomScale;
+@property (nonatomic, assign, readonly) CGPoint contentOffset;
+@property (nonatomic, assign, readonly) UIEdgeInsets contentInset;
+
 
 // This protocol disallows direct access to `selectedTextRange` property because
 // unwise usage of it can break the `delegate` behavior. So, we always have to

Libraries/Text/TextInput/Singleline/RCTUITextField.h

@@ -29,6 +29,9 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic, assign, getter=isEditable) BOOL editable;
 @property (nonatomic, getter=isScrollEnabled) BOOL scrollEnabled;
 @property (nonatomic, strong, nullable) NSString *inputAccessoryViewID;
+@property (nonatomic, assign, readonly) CGFloat zoomScale;
+@property (nonatomic, assign, readonly) CGPoint contentOffset;
+@property (nonatomic, assign, readonly) UIEdgeInsets contentInset;
 
 @end