DevTools: Show preview in console of ES6 Map, Set, WeakMap and WeakSet entries.

Source/devtools/protocol.json

 {
     "version": { "major": "1", "minor": "1" },
     "domains": [{
         "domain": "Inspector",
         "hidden": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications."
@@ skipping 727 matching lines @@
                 "id": "RemoteObject",
                 "type": "object",
                 "description": "Mirror object referencing original JavaScript object.",
                 "properties": [
                     { "name": "type", "type": "string", "enum": ["object", "function", "undefined", "string", "number", "boolean", "symbol"], "description": "Object type." },
                     { "name": "subtype", "type": "string", "optional": true, "enum": ["array", "null", "node", "regexp", "date", "map", "set"], "description": "Object subtype hint. Specified for <code>object</code> type values only." },
                     { "name": "className", "type": "string", "optional": true, "description": "Object class (constructor) name. Specified for <code>object</code> type values only." },
                     { "name": "value", "type": "any", "optional": true, "description": "Remote object value in case of primitive values or JSON values (if it was requested), or description string if the value can not be JSON-stringified (like NaN, Infinity, -Infinity, -0)." },
                     { "name": "description", "type": "string", "optional": true, "description": "String representation of the object." },
                     { "name": "objectId", "$ref": "RemoteObjectId", "optional": true, "description": "Unique object identifier (for non-primitive values)." },
-                    { "name": "preview", "$ref": "ObjectPreview", "optional": true, "description": "Preview containing abbreviated property values.", "hidden": true }
+                    { "name": "preview", "$ref": "ObjectPreview", "optional": true, "description": "Preview containing abbreviated property values. Specified for <code>object</code> type values only.", "hidden": true }
                 ]
             },
             {
                 "id": "ObjectPreview",
                 "type": "object",
                 "hidden": true,
                 "description": "Object containing abbreviated remote object value.",
                 "properties": [
+                    { "name": "type", "type": "string", "enum": ["object", "function", "undefined", "string", "number", "boolean", "symbol"], "description": "Object type." },
+                    { "name": "subtype", "type": "string", "optional": true, "enum": ["array", "null", "node", "regexp", "date", "map", "set"], "description": "Object subtype hint. Specified for <code>object</code> type values only." },
+                    { "name": "description", "type": "string", "optional": true, "description": "String representation of the object." },
                     { "name": "lossless", "type": "boolean", "description": "Determines whether preview is lossless (contains all information of the original object)." },
-                    { "name": "overflow", "type": "boolean", "description": "True iff some of the properties of the original did not fit." },
-                    { "name": "properties", "type": "array", "items": { "$ref": "PropertyPreview" }, "description": "List of the properties." }
+                    { "name": "overflow", "type": "boolean", "description": "True iff some of the properties or entries of the original object did not fit." },
+                    { "name": "properties", "type": "array", "items": { "$ref": "PropertyPreview" }, "description": "List of the properties." },
+                    { "name": "entries", "type": "array", "items": { "$ref": "EntryPreview" }, "optional": true, "description": "List of the entries. Specified for <code>map</code> and <code>set</code> subtype values only." }
                 ]
             },
             {
                 "id": "PropertyPreview",
                 "type": "object",
                 "hidden": true,
                 "properties": [
                     { "name": "name", "type": "string", "description": "Property name." },
                     { "name": "type", "type": "string", "enum": ["object", "function", "undefined", "string", "number", "boolean", "symbol", "accessor"], "description": "Object type. Accessor means that the property itself is an accessor property." },
                     { "name": "value", "type": "string", "optional": true, "description": "User-friendly property value string." },
                     { "name": "valuePreview", "$ref": "ObjectPreview", "optional": true, "description": "Nested value preview." },
                     { "name": "subtype", "type": "string", "optional": true, "enum": ["array", "null", "node", "regexp", "date", "map", "set"], "description": "Object subtype hint. Specified for <code>object</code> type values only." }
                 ]
             },
             {
+                "id": "EntryPreview",
+                "type": "object",
+                "hidden": true,
+                "properties": [
+                    { "name": "key", "$ref": "ObjectPreview", "optional": true, "description": "Preview of the key. Specified for map-like collection entries." },
+                    { "name": "value", "$ref": "ObjectPreview", "description": "Preview of the value." }
+                ]
+            },
+            {
                 "id": "PropertyDescriptor",
                 "type": "object",
                 "description": "Object property descriptor.",
                 "properties": [
                     { "name": "name", "type": "string", "description": "Property name or symbol description." },
                     { "name": "value", "$ref": "RemoteObject", "optional": true, "description": "The value associated with the property." },
                     { "name": "writable", "type": "boolean", "optional": true, "description": "True if the value associated with the property may be changed (data descriptors only)." },
                     { "name": "get", "$ref": "RemoteObject", "optional": true, "description": "A function which serves as a getter for the property, or <code>undefined</code> if there is no getter (accessor descriptors only)." },
                     { "name": "set", "$ref": "RemoteObject", "optional": true, "description": "A function which serves as a setter for the property, or <code>undefined</code> if there is no setter (accessor descriptors only)." },
                     { "name": "configurable", "type": "boolean", "description": "True if the type of this property descriptor may be changed and if the property may be deleted from the corresponding object." },
@@ skipping 3609 matching lines @@
             {
                 "name": "dataAvailable",
                 "parameters": [
                     {"name": "value", "type": "array", "items": { "$ref": "PowerEvent" }, "description": "List of power events." }
                 ],
                 "handlers": ["browser", "frontend"]
             }
         ]
     }]
 }