Web Inspector: Integrate new regionOversetChange event into inspector

Source/devtools/protocol.json

 {
     "version": { "major": "1", "minor": "0" },
     "domains": [{
         "domain": "Inspector",
         "hidden": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications."
@@ skipping 2645 matching lines @@
                 "description": "Fires when a Named Flow is removed: has no associated content nodes and regions.",
                 "hidden": true
             },
             {
                 "name": "regionLayoutUpdated",
                 "parameters": [
                     { "name": "namedFlow", "$ref": "NamedFlow", "description": "The Named Flow whose layout may have changed." }
                 ],
                 "description": "Fires when a Named Flow's layout may have changed.",
                 "hidden": true
+            },
+            {
+                "name": "regionOversetChanged",
+                "parameters": [
+                    { "name": "namedFlow", "$ref": "NamedFlow", "description": "The Named Flow containing the regions whose regionOverset values changed." }
+                ],
+                "description": "Fires if any of the regionOverset values changed in a Named Flow's region chain.",
+                "hidden": true
             }
         ]
     },
     {
         "domain": "Timeline",
         "description": "Timeline provides its clients with instrumentation records that are generated during the page runtime. Timeline instrumentation can be started and stopped using corresponding commands. While timeline is started, it is generating timeline event records.",
         "types": [
             {
                 "id": "DOMCounters",
                 "type": "object",
@@ skipping 1093 matching lines @@
                 ]
             }
         ],
         "events": [
             {
                 "name": "layerTreeDidChange"
             }
         ]
     }]
 }