DevTools: expose linkPreload bit on the network request

third_party/WebKit/Source/core/inspector/browser_protocol.json

 {
     "version": { "major": "1", "minor": "2" },
     "domains": [{
         "domain": "Inspector",
         "experimental": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications."
@@ skipping 996 matching lines @@
                 "id": "Request",
                 "type": "object",
                 "description": "HTTP request data.",
                 "properties": [
                     { "name": "url", "type": "string", "description": "Request URL." },
                     { "name": "method", "type": "string", "description": "HTTP request method." },
                     { "name": "headers", "$ref": "Headers", "description": "HTTP request headers." },
                     { "name": "postData", "type": "string", "optional": true, "description": "HTTP POST request data." },
                     { "name": "mixedContentType", "optional": true, "type": "string", "enum": ["blockable", "optionally-blockable", "none"], "description": "The mixed content status of the request, as defined in http://www.w3.org/TR/mixed-content/" },
                     { "name": "initialPriority", "$ref": "ResourcePriority", "description": "Priority of the resource request at the time request is sent."},
-                    { "name": "referrerPolicy", "type": "string", "enum": [ "unsafe-url", "no-referrer-when-downgrade", "no-referrer", "origin", "origin-when-cross-origin", "no-referrer-when-downgrade-origin-when-cross-origin" ], "description": "The referrer policy of the request, as defined in https://www.w3.org/TR/referrer-policy/" }
+                    { "name": "referrerPolicy", "type": "string", "enum": [ "unsafe-url", "no-referrer-when-downgrade", "no-referrer", "origin", "origin-when-cross-origin", "no-referrer-when-downgrade-origin-when-cross-origin" ], "description": "The referrer policy of the request, as defined in https://www.w3.org/TR/referrer-policy/" },
+                    { "name": "isLinkPreload", "type": "boolean", "optional": true, "description": "Whether is loaded via link preload." }
                 ]
             },
             {
                 "id": "SignedCertificateTimestamp",
                 "type" : "object",
                 "description": "Details of a signed certificate timestamp (SCT).",
                 "properties": [
                     { "name": "status", "type": "string", "description": "Validation status." },
                     { "name": "origin", "type": "string", "description": "Origin." },
                     { "name": "logDescription", "type": "string", "description": "Log name / description." },
@@ skipping 3518 matching lines @@
                 "name": "accepted",
                 "description": "Informs that port was successfully bound and got a specified connection id.",
                 "parameters": [
                     {"name": "port", "type": "integer", "description": "Port number that was successfully bound." },
                     {"name": "connectionId", "type": "string", "description": "Connection id to be used." }
                 ]
             }
         ]
     }]
 }