Upgrade more deps. (#2239)

Summary:
This PR upgrades more deps including gulp + some other gulp-related and build deps, and flow.

The flow upgrade involved replacing uses of emptyFunction, since Flow 0.99.0 made function types stricter adding checks for function statics. There's a good blog post about it here:

https://dev.to/wgao19/flow-0-99-callable-properties-function-statics-and-more-5c82
Pull Request resolved: #2239

Test Plan: yarn test, also played a bit with the rich text editor in the examples folder.

Reviewed By: elboman

Differential Revision: D18226234

Pulled By: mrkev

fbshipit-source-id: 98310667411984eeb24eecd48568d58283950147

package.json

@@ -49,8 +49,7 @@
     "babel-eslint": "^10.0.3",
     "babel-preset-fbjs": "^3.3.0",
     "cross-env": "^6.0.3",
-    "del": "^2.2.0",
-    "envify": "^3.4.0",
+    "del": "^5.1.0",
     "es6-shim": "^0.35.5",
     "eslint": "^6.6.0",
     "eslint-config-fbjs": "^3.1.1",
@@ -62,27 +61,25 @@
     "eslint-plugin-react": "^7.16.0",
     "eslint-plugin-relay": "^1.3.12",
     "fbjs-scripts": "^1.2.0",
-    "flow-bin": "^0.92.0",
-    "gulp": "^4.0.0",
+    "flow-bin": "^0.110.1",
+    "gulp": "^4.0.2",
     "gulp-babel": "^8.0.0",
-    "gulp-clean-css": "^2.0.3",
-    "gulp-concat-css": "^2.2.0",
+    "gulp-clean-css": "^4.2.0",
+    "gulp-concat-css": "^3.1.0",
     "gulp-derequire": "^2.1.0",
-    "gulp-flatten": "^0.2.0",
-    "gulp-header": "1.8.2",
-    "gulp-if": "^2.0.2",
-    "gulp-rename": "^1.2.2",
-    "gulp-uglify": "^1.2.0",
+    "gulp-flatten": "^0.4.0",
+    "gulp-header": "^2.0.9",
+    "gulp-if": "^3.0.0",
+    "gulp-rename": "^1.4.0",
     "gulp-util": "^3.0.6",
     "jest": "^24.9.0",
     "prettier": "1.13.6",
     "react": "^16.8.0",
     "react-dom": "^16.8.0",
     "react-test-renderer": "^16.0.0",
     "stats-webpack-plugin": "^0.6.2",
-    "through2": "^2.0.1",
+    "through2": "^3.0.1",
     "uglifyjs-webpack-plugin": "^1.1.6",
-    "vinyl-buffer": "^1.0.0",
     "webpack-stream": "^4.0.0"
   },
   "devEngines": {

src/.flowconfig

@@ -4,6 +4,7 @@
 .*/react-dom/node_modules/.*
 .*/fbjs/node_modules/.*
 .*/node_modules/invariant/.*
+.*/node_modules/fbjs/lib/emptyFunction.js.flow
 
 [include]
 ../node_modules/fbjs/lib/
@@ -37,4 +38,4 @@ suppress_comment=\\(.\\|\n\\)*\\$FlowExpectedError
 module.name_mapper='ReactDOM' -> 'react-dom'
 
 [version]
-^0.92.0
+^0.110.1

src/component/base/DraftEditor.react.js

@@ -33,7 +33,6 @@ const Style = require('Style');
 const UserAgent = require('UserAgent');
 
 const cx = require('cx');
-const emptyFunction = require('emptyFunction');
 const generateRandomKey = require('generateRandomKey');
 const getDefaultKeyBinding = require('getDefaultKeyBinding');
 const getScrollPosition = require('getScrollPosition');
@@ -136,8 +135,12 @@ class UpdateDraftEditorFlags extends React.Component<{
 class DraftEditor extends React.Component<DraftEditorProps, State> {
   static defaultProps: DraftEditorDefaultProps = {
     blockRenderMap: DefaultDraftBlockRenderMap,
-    blockRendererFn: emptyFunction.thatReturnsNull,
-    blockStyleFn: emptyFunction.thatReturns(''),
+    blockRendererFn: function() {
+      return null;
+    },
+    blockStyleFn: function() {
+      return '';
+    },
     keyBindingFn: getDefaultKeyBinding,
     readOnly: false,
     spellCheck: false,

src/model/immutable/BlockTree.js

@@ -16,13 +16,14 @@ import type CharacterMetadata from 'CharacterMetadata';
 import type ContentState from 'ContentState';
 import type {DraftDecoratorType} from 'DraftDecoratorType';
 
-const emptyFunction = require('emptyFunction');
 const findRangesImmutable = require('findRangesImmutable');
 const Immutable = require('immutable');
 
 const {List, Repeat, Record} = Immutable;
 
-const returnTrue = emptyFunction.thatReturnsTrue;
+const returnTrue = function() {
+  return true;
+};
 
 const defaultLeafRange: {
   start: ?number,