Index: package-lock.json
===================================================================
--- package-lock.json	(revision 43519)
+++ package-lock.json	(working copy)
@@ -3596,6 +3596,7 @@
 					"version": "0.0.9",
 					"bundled": true,
 					"dev": true,
+					"optional": true,
 					"requires": {
 						"inherits": "~2.0.0"
 					}
@@ -3620,7 +3621,8 @@
 				"buffer-shims": {
 					"version": "1.0.0",
 					"bundled": true,
-					"dev": true
+					"dev": true,
+					"optional": true
 				},
 				"caseless": {
 					"version": "0.12.0",
@@ -3637,12 +3639,14 @@
 				"code-point-at": {
 					"version": "1.1.0",
 					"bundled": true,
-					"dev": true
+					"dev": true,
+					"optional": true
 				},
 				"combined-stream": {
 					"version": "1.0.5",
 					"bundled": true,
 					"dev": true,
+					"optional": true,
 					"requires": {
 						"delayed-stream": "~1.0.0"
 					}
@@ -3655,17 +3659,20 @@
 				"console-control-strings": {
 					"version": "1.1.0",
 					"bundled": true,
-					"dev": true
+					"dev": true,
+					"optional": true
 				},
 				"core-util-is": {
 					"version": "1.0.2",
 					"bundled": true,
-					"dev": true
+					"dev": true,
+					"optional": true
 				},
 				"cryptiles": {
 					"version": "2.0.5",
 					"bundled": true,
 					"dev": true,
+					"optional": true,
 					"requires": {
 						"boom": "2.x.x"
 					}
@@ -3705,7 +3712,8 @@
 				"delayed-stream": {
 					"version": "1.0.0",
 					"bundled": true,
-					"dev": true
+					"dev": true,
+					"optional": true
 				},
 				"delegates": {
 					"version": "1.0.0",
@@ -3737,7 +3745,8 @@
 				"extsprintf": {
 					"version": "1.0.2",
 					"bundled": true,
-					"dev": true
+					"dev": true,
+					"optional": true
 				},
 				"forever-agent": {
 					"version": "0.6.1",
@@ -3860,6 +3869,7 @@
 					"version": "3.1.3",
 					"bundled": true,
 					"dev": true,
+					"optional": true,
 					"requires": {
 						"boom": "2.x.x",
 						"cryptiles": "2.x.x",
@@ -3907,6 +3917,7 @@
 					"version": "1.0.0",
 					"bundled": true,
 					"dev": true,
+					"optional": true,
 					"requires": {
 						"number-is-nan": "^1.0.0"
 					}
@@ -3920,7 +3931,8 @@
 				"isarray": {
 					"version": "1.0.0",
 					"bundled": true,
-					"dev": true
+					"dev": true,
+					"optional": true
 				},
 				"isstream": {
 					"version": "0.1.2",
@@ -3993,12 +4005,14 @@
 				"mime-db": {
 					"version": "1.27.0",
 					"bundled": true,
-					"dev": true
+					"dev": true,
+					"optional": true
 				},
 				"mime-types": {
 					"version": "2.1.15",
 					"bundled": true,
 					"dev": true,
+					"optional": true,
 					"requires": {
 						"mime-db": "~1.27.0"
 					}
@@ -4074,7 +4088,8 @@
 				"number-is-nan": {
 					"version": "1.0.1",
 					"bundled": true,
-					"dev": true
+					"dev": true,
+					"optional": true
 				},
 				"oauth-sign": {
 					"version": "0.8.2",
@@ -4132,7 +4147,8 @@
 				"process-nextick-args": {
 					"version": "1.0.7",
 					"bundled": true,
-					"dev": true
+					"dev": true,
+					"optional": true
 				},
 				"punycode": {
 					"version": "1.4.1",
@@ -4170,6 +4186,7 @@
 					"version": "2.2.9",
 					"bundled": true,
 					"dev": true,
+					"optional": true,
 					"requires": {
 						"buffer-shims": "~1.0.0",
 						"core-util-is": "~1.0.0",
@@ -4221,7 +4238,8 @@
 				"safe-buffer": {
 					"version": "5.0.1",
 					"bundled": true,
-					"dev": true
+					"dev": true,
+					"optional": true
 				},
 				"semver": {
 					"version": "5.3.0",
@@ -4245,6 +4263,7 @@
 					"version": "1.0.9",
 					"bundled": true,
 					"dev": true,
+					"optional": true,
 					"requires": {
 						"hoek": "2.x.x"
 					}
@@ -4278,6 +4297,7 @@
 					"version": "1.0.2",
 					"bundled": true,
 					"dev": true,
+					"optional": true,
 					"requires": {
 						"code-point-at": "^1.0.0",
 						"is-fullwidth-code-point": "^1.0.0",
@@ -4288,6 +4308,7 @@
 					"version": "1.0.1",
 					"bundled": true,
 					"dev": true,
+					"optional": true,
 					"requires": {
 						"safe-buffer": "^5.0.1"
 					}
@@ -4316,6 +4337,7 @@
 					"version": "2.2.1",
 					"bundled": true,
 					"dev": true,
+					"optional": true,
 					"requires": {
 						"block-stream": "*",
 						"fstream": "^1.0.2",
@@ -4371,7 +4393,8 @@
 				"util-deprecate": {
 					"version": "1.0.2",
 					"bundled": true,
-					"dev": true
+					"dev": true,
+					"optional": true
 				},
 				"uuid": {
 					"version": "3.0.1",
Index: src/js/_enqueues/wp/custom-header.js
===================================================================
--- src/js/_enqueues/wp/custom-header.js	(revision 43519)
+++ src/js/_enqueues/wp/custom-header.js	(working copy)
@@ -389,7 +389,8 @@
 				height: this.settings.height,
 				width: this.settings.width,
 				videoId: this.settings.videoUrl.match( VIDEO_ID_REGEX )[1],
-				events: {
+				host: location.protocol + ((this.settings.videoUrl.indexOf("youtube-nocookie") !== -1) ? "//www.youtube-nocookie.com" : "//www.youtube.com"),
+				events: {	
 					onReady: function( e ) {
 						e.target.mute();
 						handler.showControls();
Index: src/wp-includes/class-wp-customize-manager.php
===================================================================
--- src/wp-includes/class-wp-customize-manager.php	(revision 43519)
+++ src/wp-includes/class-wp-customize-manager.php	(working copy)
@@ -5853,13 +5853,13 @@
 	 * @return mixed
 	 */
 	public function _validate_external_header_video( $validity, $value ) {
-		$video = esc_url_raw( $value );
-		if ( $video ) {
-			if ( ! preg_match( '#^https?://(?:www\.)?(?:youtube\.com/watch|youtu\.be/)#', $video ) ) {
+        $video = esc_url_raw( $value );
+        if ( $video ) {
+			if ( ! preg_match( '#^https?://(?:www\.)?(youtube|youtube-nocookie)\.com/(watch|embed|youtu\.be/)#', $video ) ) {
 				$validity->add( 'invalid_url', __( 'Please enter a valid YouTube URL.' ) );
 			}
-		}
-		return $validity;
+        }
+        return $validity;
 	}
 
 	/**
Index: src/wp-includes/theme.php
===================================================================
--- src/wp-includes/theme.php	(revision 43519)
+++ src/wp-includes/theme.php	(working copy)
@@ -1461,7 +1461,7 @@
 		),
 	);
 
-	if ( preg_match( '#^https?://(?:www\.)?(?:youtube\.com/watch|youtu\.be/)#', $video_url ) ) {
+	if ( preg_match( '#^https?://(?:www\.)?(youtube|youtube-nocookie)\.com/(watch|embed|youtu\.be/)#', $video_url ) ) {
 		$settings['mimeType'] = 'video/x-youtube';
 	} elseif ( ! empty( $video_type['type'] ) ) {
 		$settings['mimeType'] = $video_type['type'];