Devtools: [LayoutEditor] highlight changed value in the SSP

Source/devtools/protocol.json

 {
     "version": { "major": "1", "minor": "1" },
     "domains": [{
         "domain": "Inspector",
         "hidden": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications.",
@@ skipping 3208 matching lines @@
                     { "name": "header", "$ref": "CSSStyleSheetHeader", "description": "Added stylesheet metainfo." }
                 ],
                 "description": "Fired whenever an active document stylesheet is added."
             },
             {
                 "name": "styleSheetRemoved",
                 "parameters": [
                     { "name": "styleSheetId", "$ref": "StyleSheetId", "description": "Identifier of the removed stylesheet." }
                 ],
                 "description": "Fired whenever an active document stylesheet is removed."
+            },
+            {
+                "name": "layoutEditorChange",
+                "parameters": [
+                    { "name": "styleSheetId", "$ref": "StyleSheetId", "description": "Identifier of the stylesheet where the modification occurred."},
+                    { "name": "changeRange", "$ref": "SourceRange", "description": "Range where the modification occurred."}
+                ]
             }
         ]
     },
     {
         "domain": "Timeline",
         "description": "Timeline domain is deprecated. Please use Tracing instead.",
         "types": [
             {
                 "id": "TimelineEvent",
                 "type": "object",
@@ skipping 1908 matching lines @@
                 ],
                 "returns": [
                     { "name": "accessibilityNode", "$ref": "AXNode", "description": "The <code>Accessibility.AXNode</code> for this DOM node, if it exists.", "optional": true }
                 ],
                 "description": "Fetches the accessibility node for this DOM node, if it exists.",
                 "hidden": true
             }
         ]
     }]
 }