Delete more redundant JSX code (facebook#28276)

Found another redundant implementation of JSX code. Not being used
anywhere so safe to delete.

packages/react/src/ReactElementValidator.js

@@ -26,10 +26,8 @@ import isArray from 'shared/isArray';
 
 import ReactCurrentOwner from './ReactCurrentOwner';
 import {isValidElement, createElement, cloneElement} from './ReactElementProd';
-import {jsxDEV} from './jsx/ReactJSXElement';
 import {setExtraStackFrame} from './ReactDebugCurrentFrame';
 import {describeUnknownElementTypeFrameInDEV} from 'shared/ReactComponentStackFrame';
-import hasOwnProperty from 'shared/hasOwnProperty';
 
 const REACT_CLIENT_REFERENCE = Symbol.for('react.client.reference');
 
@@ -277,152 +275,6 @@ function validateFragmentProps(fragment) {
   }
 }
 
-const didWarnAboutKeySpread = {};
-
-export function jsxWithValidation(
-  type,
-  props,
-  key,
-  isStaticChildren,
-  source,
-  self,
-) {
-  if (__DEV__) {
-    const validType = isValidElementType(type);
-
-    // We warn in this case but don't throw. We expect the element creation to
-    // succeed and there will likely be errors in render.
-    if (!validType) {
-      let info = '';
-      if (
-        type === undefined ||
-        (typeof type === 'object' &&
-          type !== null &&
-          Object.keys(type).length === 0)
-      ) {
-        info +=
-          ' You likely forgot to export your component from the file ' +
-          "it's defined in, or you might have mixed up default and named imports.";
-      }
-
-      const sourceInfo = getSourceInfoErrorAddendum(source);
-      if (sourceInfo) {
-        info += sourceInfo;
-      } else {
-        info += getDeclarationErrorAddendum();
-      }
-
-      let typeString;
-      if (type === null) {
-        typeString = 'null';
-      } else if (isArray(type)) {
-        typeString = 'array';
-      } else if (type !== undefined && type.$$typeof === REACT_ELEMENT_TYPE) {
-        typeString = `<${getComponentNameFromType(type.type) || 'Unknown'} />`;
-        info =
-          ' Did you accidentally export a JSX literal instead of a component?';
-      } else {
-        typeString = typeof type;
-      }
-
-      if (__DEV__) {
-        console.error(
-          'React.jsx: type is invalid -- expected a string (for ' +
-            'built-in components) or a class/function (for composite ' +
-            'components) but got: %s.%s',
-          typeString,
-          info,
-        );
-      }
-    }
-
-    const element = jsxDEV(type, props, key, source, self);
-
-    // The result can be nullish if a mock or a custom function is used.
-    // TODO: Drop this when these are no longer allowed as the type argument.
-    if (element == null) {
-      return element;
-    }
-
-    // Skip key warning if the type isn't valid since our key validation logic
-    // doesn't expect a non-string/function type and can throw confusing errors.
-    // We don't want exception behavior to differ between dev and prod.
-    // (Rendering will throw with a helpful message and as soon as the type is
-    // fixed, the key warnings will appear.)
-
-    if (validType) {
-      const children = props.children;
-      if (children !== undefined) {
-        if (isStaticChildren) {
-          if (isArray(children)) {
-            for (let i = 0; i < children.length; i++) {
-              validateChildKeys(children[i], type);
-            }
-
-            if (Object.freeze) {
-              Object.freeze(children);
-            }
-          } else {
-            console.error(
-              'React.jsx: Static children should always be an array. ' +
-                'You are likely explicitly calling React.jsxs or React.jsxDEV. ' +
-                'Use the Babel transform instead.',
-            );
-          }
-        } else {
-          validateChildKeys(children, type);
-        }
-      }
-    }
-
-    if (hasOwnProperty.call(props, 'key')) {
-      const componentName = getComponentNameFromType(type);
-      const keys = Object.keys(props).filter(k => k !== 'key');
-      const beforeExample =
-        keys.length > 0
-          ? '{key: someKey, ' + keys.join(': ..., ') + ': ...}'
-          : '{key: someKey}';
-      if (!didWarnAboutKeySpread[componentName + beforeExample]) {
-        const afterExample =
-          keys.length > 0 ? '{' + keys.join(': ..., ') + ': ...}' : '{}';
-        console.error(
-          'A props object containing a "key" prop is being spread into JSX:\n' +
-            '  let props = %s;\n' +
-            '  <%s {...props} />\n' +
-            'React keys must be passed directly to JSX without using spread:\n' +
-            '  let props = %s;\n' +
-            '  <%s key={someKey} {...props} />',
-          beforeExample,
-          componentName,
-          afterExample,
-          componentName,
-        );
-        didWarnAboutKeySpread[componentName + beforeExample] = true;
-      }
-    }
-
-    if (type === REACT_FRAGMENT_TYPE) {
-      validateFragmentProps(element);
-    } else {
-      validatePropTypes(element);
-    }
-
-    return element;
-  }
-}
-
-// These two functions exist to still get child warnings in dev
-// even with the prod transform. This means that jsxDEV is purely
-// opt-in behavior for better messages but that we won't stop
-// giving you warnings if you use production apis.
-export function jsxWithValidationStatic(type, props, key) {
-  return jsxWithValidation(type, props, key, true);
-}
-
-export function jsxWithValidationDynamic(type, props, key) {
-  return jsxWithValidation(type, props, key, false);
-}
-
 export function createElementWithValidation(type, props, children) {
   const validType = isValidElementType(type);