Fixed wrong placeholder size calculation in multiline text input mode (…

…#23682)

Summary:
We have the wrong calculation of placeholder size currently, leads `contentSize` or some things inaccuracy.

[iOS] [Fixed] - Fixed wrong placeholder size calculation in multiline text input mode
Pull Request resolved: #23682

Differential Revision: D14255932

Pulled By: cpojer

fbshipit-source-id: a1f40e90fc2c848579694965da8316fae9e5c4c5

Libraries/Text/TextInput/Multiline/RCTUITextView.m

@@ -184,7 +184,8 @@ - (CGSize)placeholderSize
 {
   UIEdgeInsets textContainerInset = self.textContainerInset;
   NSString *placeholder = self.placeholder ?: @"";
-  CGSize placeholderSize = [placeholder sizeWithAttributes:@{NSFontAttributeName: self.font ?: defaultPlaceholderFont()}];
+  CGSize maxPlaceholderSize = CGSizeMake(UIEdgeInsetsInsetRect(self.bounds, textContainerInset).size.width, CGFLOAT_MAX);
+  CGSize placeholderSize = [placeholder boundingRectWithSize:maxPlaceholderSize options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName: self.font ?: defaultPlaceholderFont()} context:nil].size;
   placeholderSize = CGSizeMake(RCTCeilPixelValue(placeholderSize.width), RCTCeilPixelValue(placeholderSize.height));
   placeholderSize.width += textContainerInset.left + textContainerInset.right;
   placeholderSize.height += textContainerInset.top + textContainerInset.bottom;