[ReactNative] Fix RCTTextField crash on iOS7

Summary:
RCTTextField was its own delegate, that was causing a stall on the main thread,
see more here:
http://stackoverflow.com/questions/19758025/uitextfield-delegate-jumping-to-100-cpu-usage-and-crashing-upon-using-keyboard

Libraries/Text/RCTTextField.h

@@ -11,7 +11,7 @@
 
 @class RCTEventDispatcher;
 
-@interface RCTTextField : UITextField<UITextFieldDelegate>
+@interface RCTTextField : UITextField
 
 @property (nonatomic, assign) BOOL caretHidden;
 @property (nonatomic, assign) BOOL autoCorrect;
@@ -22,5 +22,6 @@
 @property (nonatomic, strong) NSNumber *maxLength;
 
 - (instancetype)initWithEventDispatcher:(RCTEventDispatcher *)eventDispatcher NS_DESIGNATED_INITIALIZER;
+- (void)textFieldDidChange;
 
 @end

Libraries/Text/RCTTextField.m

@@ -27,12 +27,11 @@
   if ((self = [super initWithFrame:CGRectZero])) {
     RCTAssert(eventDispatcher, @"eventDispatcher is a required parameter");
     _eventDispatcher = eventDispatcher;
-    [self addTarget:self action:@selector(_textFieldDidChange) forControlEvents:UIControlEventEditingChanged];
+    [self addTarget:self action:@selector(textFieldDidChange) forControlEvents:UIControlEventEditingChanged];
-    [self addTarget:self action:@selector(_textFieldBeginEditing) forControlEvents:UIControlEventEditingDidBegin];
+    [self addTarget:self action:@selector(textFieldBeginEditing) forControlEvents:UIControlEventEditingDidBegin];
-    [self addTarget:self action:@selector(_textFieldEndEditing) forControlEvents:UIControlEventEditingDidEnd];
+    [self addTarget:self action:@selector(textFieldEndEditing) forControlEvents:UIControlEventEditingDidEnd];
-    [self addTarget:self action:@selector(_textFieldSubmitEditing) forControlEvents:UIControlEventEditingDidEndOnExit];
+    [self addTarget:self action:@selector(textFieldSubmitEditing) forControlEvents:UIControlEventEditingDidEndOnExit];
     _reactSubviews = [[NSMutableArray alloc] init];
-    self.delegate = self;
   }
   return self;
 }
@@ -40,31 +39,6 @@
 RCT_NOT_IMPLEMENTED(-initWithFrame:(CGRect)frame)
 RCT_NOT_IMPLEMENTED(-initWithCoder:(NSCoder *)aDecoder)
 
-- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
-{
-  if (_maxLength == nil || [string isEqualToString:@"\n"]) {  // Make sure forms can be submitted via return
-    return YES;
-  }
-  NSUInteger allowedLength = _maxLength.integerValue - textField.text.length + range.length;
-  if (string.length > allowedLength) {
-    if (string.length > 1) {
-      // Truncate the input string so the result is exactly maxLength
-      NSString *limitedString = [string substringToIndex:allowedLength];
-      NSMutableString *newString = textField.text.mutableCopy;
-      [newString replaceCharactersInRange:range withString:limitedString];
-      textField.text = newString;
-      // Collapse selection at end of insert to match normal paste behavior
-      UITextPosition *insertEnd = [textField positionFromPosition:textField.beginningOfDocument
-                                                          offset:(range.location + allowedLength)];
-      textField.selectedTextRange = [textField textRangeFromPosition:insertEnd toPosition:insertEnd];
-      [self _textFieldDidChange];
-    }
-    return NO;
-  } else {
-    return YES;
-  }
-}
-
 - (void)setText:(NSString *)text
 {
   NSInteger eventLag = _nativeEventCount - _mostRecentEventCount;
@@ -154,7 +128,7 @@ static void RCTUpdatePlaceholder(RCTTextField *self)
   return self.autocorrectionType == UITextAutocorrectionTypeYes;
 }
 
-- (void)_textFieldDidChange
+- (void)textFieldDidChange
 {
   _nativeEventCount++;
   [_eventDispatcher sendTextEventWithType:RCTTextEventTypeChange
@@ -163,14 +137,14 @@ static void RCTUpdatePlaceholder(RCTTextField *self)
                                eventCount:_nativeEventCount];
 }
 
-- (void)_textFieldEndEditing
+- (void)textFieldEndEditing
 {
   [_eventDispatcher sendTextEventWithType:RCTTextEventTypeEnd
                                  reactTag:self.reactTag
                                      text:self.text
                                eventCount:_nativeEventCount];
 }
-- (void)_textFieldSubmitEditing
+- (void)textFieldSubmitEditing
 {
   [_eventDispatcher sendTextEventWithType:RCTTextEventTypeSubmit
                                  reactTag:self.reactTag
@@ -178,7 +152,7 @@ static void RCTUpdatePlaceholder(RCTTextField *self)
                                eventCount:_nativeEventCount];
 }
 
-- (void)_textFieldBeginEditing
+- (void)textFieldBeginEditing
 {
   if (_selectTextOnFocus) {
     dispatch_async(dispatch_get_main_queue(), ^{

Libraries/Text/RCTTextFieldManager.m

@@ -14,13 +14,44 @@
 #import "RCTSparseArray.h"
 #import "RCTTextField.h"
 
+@interface RCTTextFieldManager() <UITextFieldDelegate>
+
+@end
+
 @implementation RCTTextFieldManager
 
 RCT_EXPORT_MODULE()
 
 - (UIView *)view
 {
-  return [[RCTTextField alloc] initWithEventDispatcher:self.bridge.eventDispatcher];
+  RCTTextField *textField = [[RCTTextField alloc] initWithEventDispatcher:self.bridge.eventDispatcher];
+  textField.delegate = self;
+  return textField;
+}
+
+- (BOOL)textField:(RCTTextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
+{
+  if (textField.maxLength == nil || [string isEqualToString:@"\n"]) {  // Make sure forms can be submitted via return
+    return YES;
+  }
+  NSUInteger allowedLength = textField.maxLength.integerValue - textField.text.length + range.length;
+  if (string.length > allowedLength) {
+    if (string.length > 1) {
+      // Truncate the input string so the result is exactly maxLength
+      NSString *limitedString = [string substringToIndex:allowedLength];
+      NSMutableString *newString = textField.text.mutableCopy;
+      [newString replaceCharactersInRange:range withString:limitedString];
+      textField.text = newString;
+      // Collapse selection at end of insert to match normal paste behavior
+      UITextPosition *insertEnd = [textField positionFromPosition:textField.beginningOfDocument
+                                                          offset:(range.location + allowedLength)];
+      textField.selectedTextRange = [textField textRangeFromPosition:insertEnd toPosition:insertEnd];
+      [textField textFieldDidChange];
+    }
+    return NO;
+  } else {
+    return YES;
+  }
 }
 
 RCT_EXPORT_VIEW_PROPERTY(caretHidden, BOOL)