Caption editing in the media modal library.

* Adds a `describe` option to the workflow controller to support inline caption editing.
* For images, descriptions are mapped to the `caption` attribute.
* For other media items, descriptions are mapped to the `title` attribute.
* Descriptions are saved when the textarea's `change` event fires (i.e. when the textarea is blurred).

fixes #21807, see #21390.


git-svn-id: https://develop.svn.wordpress.org/trunk@22173 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/css/media-views.css

@@ -246,16 +246,9 @@
 .attachment {
 	position: relative;
 	float: left;
-	width: 199px;
-	height: 199px;
 
 	padding: 0;
 	margin: 0 10px 20px;
-	box-shadow:
-		inset 0 0 15px rgba( 0, 0, 0, 0.1 ),
-		inset 0 0 0 1px rgba( 0, 0, 0, 0.05 );
-	background: #eee;
-	cursor: pointer;
 	color: #464646;
 
 	-webkit-user-select: none;
@@ -281,12 +274,15 @@
 }
 
 .attachment-preview {
-	position: absolute;
-	top: 0;
-	left: 0;
-	right: 0;
-	bottom: 0;
+	position: relative;
+	width: 199px;
+	height: 199px;
 	overflow: hidden;
+	box-shadow:
+		inset 0 0 15px rgba( 0, 0, 0, 0.1 ),
+		inset 0 0 0 1px rgba( 0, 0, 0, 0.05 );
+	background: #eee;
+	cursor: pointer;
 }
 
 .attachment .icon,
@@ -390,6 +386,18 @@
 	display: block;
 }
 
+.attachment .describe {
+	position: relative;
+	display: block;
+	width: 100%;
+	height: 66px;
+	margin: -1px 0 0;
+	padding: 8px;
+	font-size: 12px;
+	resize: none;
+	border-radius: 0;
+}
+
 
 /* Square crop with overflow visible on hover. */
 /*