Better TextInput: Simplified focus/first-responder management on iOS

Summary:
Pair `reactWillMakeFirstResponder` and `reactDidMakeFirstResponder` was replaced with just `reactFocus` method
which is supposed to incapsulate all "focus" and "focus-later-if-needed" functionality.

Reviewed By: mmmulani

Differential Revision: D4664626

fbshipit-source-id: 8d3b7935ca26d32ba1d1826a585cce0396fcc885

Libraries/Text/RCTTextField.m

@@ -48,7 +48,6 @@
 @implementation RCTTextField
 {
   RCTEventDispatcher *_eventDispatcher;
-  BOOL _jsRequestingFirstResponder;
   NSInteger _nativeEventCount;
   BOOL _submitted;
   UITextRange *_previousSelectionRange;
@@ -94,16 +93,6 @@ RCT_NOT_IMPLEMENTED(- (instancetype)initWithCoder:(NSCoder *)aDecoder)
                                eventCount:_nativeEventCount];
 }
 
-- (void)didUpdateFocusInContext:(UIFocusUpdateContext *)context withAnimationCoordinator:(UIFocusAnimationCoordinator *)coordinator
-{
-  [super didUpdateFocusInContext:context withAnimationCoordinator:coordinator];
-  if(context.nextFocusedView == self) {
-    _jsRequestingFirstResponder = YES;
-  } else {
-    _jsRequestingFirstResponder = NO;
-  }
-}
-
 // This method is overridden for `onKeyPress`. The manager
 // will not send a keyPress for text that was pasted.
 - (void)paste:(id)sender
@@ -285,21 +274,6 @@ static void RCTUpdatePlaceholder(RCTTextField *self)
   }
 }
 
-- (BOOL)canBecomeFirstResponder
-{
-  return _jsRequestingFirstResponder;
-}
-
-- (void)reactWillMakeFirstResponder
-{
-  _jsRequestingFirstResponder = YES;
-}
-
-- (void)reactDidMakeFirstResponder
-{
-  _jsRequestingFirstResponder = NO;
-}
-
 - (BOOL)resignFirstResponder
 {
   BOOL result = [super resignFirstResponder];
@@ -314,6 +288,11 @@ static void RCTUpdatePlaceholder(RCTTextField *self)
   return result;
 }
 
+- (void)didMoveToWindow
+{
+  [self reactFocusIfNeeded];
+}
+
 #pragma mark - UITextFieldDelegate (Proxied)
 
 - (BOOL)shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string

Libraries/Text/RCTTextView.m

@@ -332,7 +332,7 @@ static NSAttributedString *removeReactTagFromString(NSAttributedString *string)
                                          text:self.text
                                           key:nil
                                    eventCount:_nativeEventCount];
-      [self resignFirstResponder];
+      [_textView resignFirstResponder];
       return NO;
     }
   }
@@ -541,40 +541,24 @@ static BOOL findMismatch(NSString *first, NSString *second, NSRange *firstRange,
                                eventCount:_nativeEventCount];
 }
 
-#pragma mark - UIResponder
+#pragma mark - Focus control deledation
 
-- (BOOL)isFirstResponder
+- (void)reactFocus
 {
-  return [_textView isFirstResponder];
+  [_textView reactFocus];
 }
 
-- (BOOL)canBecomeFirstResponder
+- (void)reactBlur
 {
-  return [_textView canBecomeFirstResponder];
+  [_textView reactBlur];
 }
 
-- (void)reactWillMakeFirstResponder
+- (void)didMoveToWindow
 {
-  [_textView reactWillMakeFirstResponder];
+  [_textView reactFocusIfNeeded];
 }
 
-- (BOOL)becomeFirstResponder
-{
-  return [_textView becomeFirstResponder];
-}
-
-- (void)reactDidMakeFirstResponder
-{
-  [_textView reactDidMakeFirstResponder];
-}
-
-- (BOOL)resignFirstResponder
-{
-  [super resignFirstResponder];
-  return [_textView resignFirstResponder];
-}
-
-#pragma mark - Content Size
+#pragma mark - Content size
 
 - (CGSize)contentSize
 {

Libraries/Text/RCTUITextView.m

@@ -9,9 +9,10 @@
 
 #import "RCTUITextView.h"
 
+#import <React/UIView+React.h>
+
 @implementation RCTUITextView
 {
-  BOOL _jsRequestingFirstResponder;
   UILabel *_placeholderView;
   UITextView *_detachedTextView;
 }
@@ -69,31 +70,6 @@ static UIColor *defaultPlaceholderTextColor()
   [self invalidatePlaceholderVisibility];
 }
 
-#pragma mark - UIResponder
-
-- (void)reactWillMakeFirstResponder
-{
-  _jsRequestingFirstResponder = YES;
-}
-
-- (BOOL)canBecomeFirstResponder
-{
-  return _jsRequestingFirstResponder;
-}
-
-- (void)reactDidMakeFirstResponder
-{
-  _jsRequestingFirstResponder = NO;
-}
-
-- (void)didMoveToWindow
-{
-  if (_jsRequestingFirstResponder) {
-    [self becomeFirstResponder];
-    [self reactDidMakeFirstResponder];
-  }
-}
-
 #pragma mark - Overrides
 
 - (void)setFont:(UIFont *)font