Add the ability to drag and drop files directly onto the editor.

The file will then begin to upload and the media manager will open.

props kovshenin.
see #19845.


git-svn-id: https://develop.svn.wordpress.org/trunk@27343 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/media-template.php

@@ -41,6 +41,12 @@ function wp_print_media_templates() {
 		</div>
 	</script>
 
+	<script type="text/html" id="tmpl-uploader-editor">
+		<div class="uploader-editor-content">
+			<h3><?php _e( 'Drop files to upload' ); ?></h3>
+		</div>
+	</script>
+
 	<script type="text/html" id="tmpl-uploader-inline">
 		<# var messageClass = data.message ? 'has-upload-message' : 'no-upload-message'; #>
 		<div class="uploader-inline-content {{ messageClass }}">