Remove chrome fix (#15665)

We only support the last two major Chrome versions.

The current version is 74, and a patch for this has landed upstream
in chrome 72 https://bugs.chromium.org/p/chromium/issues/detail?id=737691

packages/components/src/draggable/index.js

@@ -14,20 +14,14 @@ const cloneWrapperClass = 'components-draggable__clone';
 const cloneHeightTransformationBreakpoint = 700;
 const clonePadding = 20;
 
-const isChromeUA = ( ) => /Chrome/i.test( window.navigator.userAgent );
-const documentHasIframes = ( ) => [ ...document.getElementById( 'editor' ).querySelectorAll( 'iframe' ) ].length > 0;
-
 class Draggable extends Component {
 	constructor() {
 		super( ...arguments );
 
 		this.onDragStart = this.onDragStart.bind( this );
 		this.onDragOver = this.onDragOver.bind( this );
-		this.onDrop = this.onDrop.bind( this );
 		this.onDragEnd = this.onDragEnd.bind( this );
 		this.resetDragState = this.resetDragState.bind( this );
-
-		this.isChromeAndHasIframes = false;
 	}
 
 	componentWillUnmount() {
@@ -36,21 +30,21 @@ class Draggable extends Component {
 
 	/**
 	 * Removes the element clone, resets cursor, and removes drag listener.
-	 * @param  {Object} event     The non-custom DragEvent.
+	 *
+	 * @param  {Object} event The non-custom DragEvent.
 	 */
 	onDragEnd( event ) {
 		const { onDragEnd = noop } = this.props;
-		if ( event ) {
-			event.preventDefault();
-		}
+		event.preventDefault();
 
 		this.resetDragState();
 		this.props.setTimeout( onDragEnd );
 	}
 
-	/*
+	/**
 	 * Updates positioning of element clone based on mouse movement during dragging.
-	 * @param  {Object} event     The non-custom DragEvent.
+	 *
+	 * @param  {Object} event The non-custom DragEvent.
 	 */
 	onDragOver( event ) {
 		this.cloneWrapper.style.top =
@@ -63,21 +57,17 @@ class Draggable extends Component {
 		this.cursorTop = event.clientY;
 	}
 
-	onDrop( ) {
-		// As per https://html.spec.whatwg.org/multipage/dnd.html#dndevents
-		// the target node for the dragend is the source node that started the drag operation,
-		// while drop event's target is the current target element.
-		this.onDragEnd( null );
-	}
-
 	/**
-	 *  - Clones the current element and spawns clone over original element.
-	 *  - Adds a fake temporary drag image to avoid browser defaults.
-	 *  - Sets transfer data.
-	 *  - Adds dragover listener.
-	 * @param  {Object} event					The non-custom DragEvent.
-	 * @param  {string} elementId				The HTML id of the element to be dragged.
-	 * @param  {Object} transferData			The data to be set to the event's dataTransfer - to be accessible in any later drop logic.
+	 * This method does a couple of things:
+	 *
+	 * - Clones the current element and spawns clone over original element.
+	 * - Adds a fake temporary drag image to avoid browser defaults.
+	 * - Sets transfer data.
+	 * - Adds dragover listener.
+	 *
+	 * @param  {Object} event The non-custom DragEvent.
+	 * @param  {string} elementId The HTML id of the element to be dragged.
+	 * @param  {Object} transferData The data to be set to the event's dataTransfer - to be accessible in any later drop logic.
 	 */
 	onDragStart( event ) {
 		const { elementId, transferData, onDragStart = noop } = this.props;
@@ -140,17 +130,6 @@ class Draggable extends Component {
 		document.body.classList.add( 'is-dragging-components-draggable' );
 		document.addEventListener( 'dragover', this.onDragOver );
 
-		// Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=737691#c8
-		// dragend event won't be dispatched in the chrome browser
-		// when iframes are affected by the drag operation. So, in that case,
-		// we use the drop event to wrap up the dragging operation.
-		// This way the hack is contained to a specific use case and the external API
-		// still relies mostly on the dragend event.
-		if ( isChromeUA() && documentHasIframes() ) {
-			this.isChromeAndHasIframes = true;
-			document.addEventListener( 'drop', this.onDrop );
-		}
-
 		this.props.setTimeout( onDragStart );
 	}
 
@@ -166,11 +145,6 @@ class Draggable extends Component {
 			this.cloneWrapper = null;
 		}
 
-		if ( this.isChromeAndHasIframes ) {
-			this.isChromeAndHasIframes = false;
-			document.removeEventListener( 'drop', this.onDrop );
-		}
-
 		// Reset cursor.
 		document.body.classList.remove( 'is-dragging-components-draggable' );
 	}