diff -r 490d5cc509ed -r cf61fcea0001 wp/wp-includes/js/wp-emoji-loader.js
--- a/wp/wp-includes/js/wp-emoji-loader.js	Tue Jun 09 11:14:17 2015 +0000
+++ b/wp/wp-includes/js/wp-emoji-loader.js	Mon Oct 14 17:39:30 2019 +0200
@@ -1,5 +1,35 @@
 ( function( window, document, settings ) {
-	var src, ready;
+	var src, ready, ii, tests;
+
+	/*
+	 * Create a canvas element for testing native browser support
+	 * of emoji.
+	 */
+	var canvas = document.createElement( 'canvas' );
+	var context = canvas.getContext && canvas.getContext( '2d' );
+
+	/**
+	 * Check if two sets of Emoji characters render the same.
+	 *
+	 * @param set1 array Set of Emoji characters.
+	 * @param set2 array Set of Emoji characters.
+	 * @returns {boolean} True if the two sets render the same.
+	 */
+	function emojiSetsRenderIdentically( set1, set2 ) {
+		var stringFromCharCode = String.fromCharCode;
+
+		// Cleanup from previous test.
+		context.clearRect( 0, 0, canvas.width, canvas.height );
+		context.fillText( stringFromCharCode.apply( this, set1 ), 0, 0 );
+		var rendered1 = canvas.toDataURL();
+
+		// Cleanup from previous test.
+		context.clearRect( 0, 0, canvas.width, canvas.height );
+		context.fillText( stringFromCharCode.apply( this, set2 ), 0, 0 );
+		var rendered2 = canvas.toDataURL();
+
+		return rendered1 === rendered2;
+	}
 
 	/**
 	 * Detect if the browser supports rendering emoji or flag emoji. Flag emoji are a single glyph
@@ -7,12 +37,11 @@
 	 *
 	 * @since 4.2.0
 	 *
-	 * @param type {String} Whether to test for support of "simple" or "flag" emoji.
+	 * @param type {String} Whether to test for support of "flag" or "emoji".
 	 * @return {Boolean} True if the browser can render emoji, false if it cannot.
 	 */
 	function browserSupportsEmoji( type ) {
-		var canvas = document.createElement( 'canvas' ),
-			context = canvas.getContext && canvas.getContext( '2d' );
+		var isIdentical;
 
 		if ( ! context || ! context.fillText ) {
 			return false;
@@ -26,48 +55,88 @@
 		context.textBaseline = 'top';
 		context.font = '600 32px Arial';
 
-		if ( type === 'flag' ) {
-			/*
-			 * This works because the image will be one of three things:
-			 * - Two empty squares, if the browser doesn't render emoji
-			 * - Two squares with 'G' and 'B' in them, if the browser doesn't render flag emoji
-			 * - The British flag
-			 *
-			 * The first two will encode to small images (1-2KB data URLs), the third will encode
-			 * to a larger image (4-5KB data URL).
-			 */
-			context.fillText( String.fromCharCode( 55356, 56812, 55356, 56807 ), 0, 0 );
-			return canvas.toDataURL().length > 3000;
-		} else {
-			/*
-			 * This creates a smiling emoji, and checks to see if there is any image data in the
-			 * center pixel. In browsers that don't support emoji, the character will be rendered
-			 * as an empty square, so the center pixel will be blank.
-			 */
-			context.fillText( String.fromCharCode( 55357, 56835 ), 0, 0 );
-			return context.getImageData( 16, 16, 1, 1 ).data[0] !== 0;
+		switch ( type ) {
+			case 'flag':
+				/*
+				 * Test for UN flag compatibility. This is the least supported of the letter locale flags,
+				 * so gives us an easy test for full support.
+				 *
+				 * To test for support, we try to render it, and compare the rendering to how it would look if
+				 * the browser doesn't render it correctly ([U] + [N]).
+				 */
+				isIdentical = emojiSetsRenderIdentically(
+					[ 55356, 56826, 55356, 56819 ],
+					[ 55356, 56826, 8203, 55356, 56819 ]
+				);
+
+				if ( isIdentical ) {
+					return false;
+				}
+
+				/*
+				 * Test for English flag compatibility. England is a country in the United Kingdom, it
+				 * does not have a two letter locale code but rather an five letter sub-division code.
+				 *
+				 * To test for support, we try to render it, and compare the rendering to how it would look if
+				 * the browser doesn't render it correctly (black flag emoji + [G] + [B] + [E] + [N] + [G]).
+				 */
+				isIdentical = emojiSetsRenderIdentically(
+					[ 55356, 57332, 56128, 56423, 56128, 56418, 56128, 56421, 56128, 56430, 56128, 56423, 56128, 56447 ],
+					[ 55356, 57332, 8203, 56128, 56423, 8203, 56128, 56418, 8203, 56128, 56421, 8203, 56128, 56430, 8203, 56128, 56423, 8203, 56128, 56447 ]
+				);
+
+				return ! isIdentical;
+			case 'emoji':
+				/*
+				 * She's the hero Emoji deserves, but not the one it needs right now.
+				 *
+				 * To test for support, try to render a new emoji (female superhero),
+				 * then compare it to how it would look if the browser doesn't render it correctly
+				 * (superhero + female sign).
+				 */
+				isIdentical = emojiSetsRenderIdentically(
+					[55358, 56760, 9792, 65039],
+					[55358, 56760, 8203, 9792, 65039]
+				);
+				return ! isIdentical;
 		}
+
+		return false;
 	}
 
 	function addScript( src ) {
 		var script = document.createElement( 'script' );
 
 		script.src = src;
-		script.type = 'text/javascript';
+		script.defer = script.type = 'text/javascript';
 		document.getElementsByTagName( 'head' )[0].appendChild( script );
 	}
 
+	tests = Array( 'flag', 'emoji' );
+
 	settings.supports = {
-		simple: browserSupportsEmoji( 'simple' ),
-		flag:   browserSupportsEmoji( 'flag' )
+		everything: true,
+		everythingExceptFlag: true
 	};
 
+	for( ii = 0; ii < tests.length; ii++ ) {
+		settings.supports[ tests[ ii ] ] = browserSupportsEmoji( tests[ ii ] );
+
+		settings.supports.everything = settings.supports.everything && settings.supports[ tests[ ii ] ];
+
+		if ( 'flag' !== tests[ ii ] ) {
+			settings.supports.everythingExceptFlag = settings.supports.everythingExceptFlag && settings.supports[ tests[ ii ] ];
+		}
+	}
+
+	settings.supports.everythingExceptFlag = settings.supports.everythingExceptFlag && ! settings.supports.flag;
+
 	settings.DOMReady = false;
 	settings.readyCallback = function() {
 		settings.DOMReady = true;
 	};
 
-	if ( ! settings.supports.simple || ! settings.supports.flag ) {
+	if ( ! settings.supports.everything ) {
 		ready = function() {
 			settings.readyCallback();
 		};