DevTools: expose initial priority of a resource request in Network.requestWillBeSent

Source/devtools/protocol.json

 {
     "version": { "major": "1", "minor": "1" },
     "domains": [{
         "domain": "Inspector",
         "hidden": true,
         "types": [],
         "commands": [
             {
                 "name": "enable",
                 "description": "Enables inspector domain notifications.",
@@ skipping 1155 matching lines @@
                     { "name": "sslStart", "type": "number", "description": "Started SSL handshake." },
                     { "name": "sslEnd", "type": "number", "description": "Finished SSL handshake." },
                     { "name": "workerStart", "type": "number", "description": "Started running ServiceWorker.", "hidden": true },
                     { "name": "workerReady", "type": "number", "description": "Finished Starting ServiceWorker.", "hidden": true },
                     { "name": "sendStart", "type": "number", "description": "Started sending request." },
                     { "name": "sendEnd", "type": "number", "description": "Finished sending request." },
                     { "name": "receiveHeadersEnd", "type": "number", "description": "Finished receiving response headers." }
                 ]
             },
             {
+                "id": "ResourcePriority",
+                "type": "string",
+                "enum": ["VeryLow", "Low", "Medium", "High", "VeryHigh"],
+                "description": "Loading priority of a resource request."
+            },
+            {
                 "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", "$ref": "Headers", "description": "HTTP request headers." },
                     { "name": "postData", "type": "string", "optional": true, "description": "HTTP POST request data." },
-                    { "name": "mixedContentType", "optional": true, "type": "string", "enum": ["blockable", "optionally-blockable", "none"], "description": "The mixed content status of the request, as defined in http://www.w3.org/TR/mixed-content/" }
+                    { "name": "mixedContentType", "optional": true, "type": "string", "enum": ["blockable", "optionally-blockable", "none"], "description": "The mixed content status of the request, as defined in http://www.w3.org/TR/mixed-content/" },
+                    { "name": "initialPriority", "$ref": "ResourcePriority", "description": "Priority of the resource request at the time request is sent."}
                 ]
             },
             {
                 "id": "CertificateId",
                 "type": "integer",
                 "description": "An internal certificate ID value."
             },
             {
                 "id": "CertificateSubject",
                 "type": "object",
@@ skipping 4026 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
             }
         ]
     }]
 }