Index: wp-includes/wp-diff.php
===================================================================
--- wp-includes/wp-diff.php	(revision 24939)
+++ wp-includes/wp-diff.php	(working copy)
@@ -154,7 +154,7 @@
 		$r = '';
 		foreach ($lines as $line) {
 			if ( $encode )
-				$line = htmlspecialchars( $line );
+				$line = apply_filters( 'process_revision_diff_html', htmlspecialchars( $line ), $line );
 			if ( $this->_show_split_view ) {
 				$r .= '<tr>' . $this->emptyLine() . $this->emptyLine() . $this->addedLine( $line ) . "</tr>\n";
 			} else {
@@ -176,7 +176,7 @@
 		$r = '';
 		foreach ($lines as $line) {
 			if ( $encode )
-				$line = htmlspecialchars( $line );
+				$line = apply_filters( 'process_revision_diff_html', htmlspecialchars( $line ), $line );
 			if ( $this->_show_split_view ) {
 				$r .= '<tr>' . $this->deletedLine( $line ) . $this->emptyLine() . $this->emptyLine() . "</tr>\n";
 			} else {
@@ -199,7 +199,7 @@
 		$r = '';
 		foreach ($lines as $line) {
 			if ( $encode )
-				$line = htmlspecialchars( $line );
+				$line = apply_filters( 'process_revision_diff_html', htmlspecialchars( $line ), $line );
 			if (  $this->_show_split_view ) {
 				$r .= '<tr>' . $this->contextLine( $line ) . $this->emptyLine() . $this->contextLine( $line )  . "</tr>\n";
 			} else {
Index: wp-admin/includes/revision.php
===================================================================
--- wp-admin/includes/revision.php	(revision 24939)
+++ wp-admin/includes/revision.php	(working copy)
@@ -58,7 +58,8 @@
 		$content_from = $compare_from ? apply_filters( "_wp_post_revision_field_$field", $compare_from->$field, $field, $compare_from, 'from' ) : '';
 		$content_to = apply_filters( "_wp_post_revision_field_$field", $compare_to->$field, $field, $compare_to, 'to' );
 
-		$diff = wp_text_diff( $content_from, $content_to, array( 'show_split_view' => true ) );
+		$show_split_view = apply_filters( 'show_revisions_split_view', true );
+		$diff = wp_text_diff( $content_from, $content_to, array( 'show_split_view' => $show_split_view ) );
 
 		if ( ! $diff && 'post_title' === $field ) {
 			// It's a better user experience to still show the Title, even if it didn't change.