Implement autoFocus in TextInput

Summary:
Changelog: [Internal]

Prop autoFocus was not implemented in Fabric's TextInput.

Reviewed By: mdvacca

Differential Revision: D22019333

fbshipit-source-id: 03f043b93e1079a5d0bff55b08ebc9d2f973c55b

React/Fabric/Mounting/ComponentViews/TextInput/RCTTextInputComponentView.mm

@@ -54,6 +54,7 @@ using namespace facebook::react;
    * In multiline text input this is undesirable as we don't want to be sending events for changes that JS triggered.
    */
   BOOL _comingFromJS;
+  BOOL _didMoveToWindow;
 }
 
 - (instancetype)initWithFrame:(CGRect)frame
@@ -67,12 +68,26 @@ using namespace facebook::react;
     _backedTextInputView.textInputDelegate = self;
     _ignoreNextTextInputCall = NO;
     _comingFromJS = NO;
+    _didMoveToWindow = NO;
     [self addSubview:_backedTextInputView];
   }
 
   return self;
 }
 
+- (void)didMoveToWindow
+{
+  [super didMoveToWindow];
+
+  if (self.window && !_didMoveToWindow) {
+    auto const &props = *std::static_pointer_cast<TextInputProps const>(_props);
+    if (props.autoFocus) {
+      [_backedTextInputView becomeFirstResponder];
+    }
+    _didMoveToWindow = YES;
+  }
+}
+
 #pragma mark - RCTComponentViewProtocol
 
 + (ComponentDescriptorProvider)componentDescriptorProvider
@@ -237,6 +252,7 @@ using namespace facebook::react;
   _comingFromJS = NO;
   _lastStringStateWasUpdatedWith = nil;
   _ignoreNextTextInputCall = NO;
+  _didMoveToWindow = NO;
 }
 
 #pragma mark - RCTComponentViewProtocol

ReactCommon/fabric/components/textinput/iostextinput/TextInputProps.cpp

@@ -54,7 +54,9 @@ TextInputProps::TextInputProps(
           rawProps,
           "mostRecentEventCount",
           sourceProps.mostRecentEventCount,
-          {})){};
+          {})),
+      autoFocus(
+          convertRawProp(rawProps, "autoFocus", sourceProps.autoFocus, {})){};
 
 TextAttributes TextInputProps::getEffectiveTextAttributes() const {
   auto result = TextAttributes::defaultTextAttributes();

ReactCommon/fabric/components/textinput/iostextinput/TextInputProps.h

@@ -53,6 +53,8 @@ class TextInputProps final : public ViewProps, public BaseTextProps {
   std::string const text{};
   int const mostRecentEventCount{0};
 
+  bool autoFocus{false};
+
   /*
    * Accessors
    */