[Devtools] Add stacktrace to protocol for scriptParsed event

src/inspector/js_protocol.json

 {
     "version": { "major": "1", "minor": "2" },
     "domains": [
     {
         "domain": "Schema",
         "description": "Provides information about the protocol schema.",
         "types": [
             {
                 "id": "Domain",
                 "type": "object",
@@ skipping 695 matching lines @@
                     { "name": "startColumn", "type": "integer", "description": "Column offset of the script within the resource with given URL." },
                     { "name": "endLine", "type": "integer", "description": "Last line of the script." },
                     { "name": "endColumn", "type": "integer", "description": "Length of the last line of the script." },
                     { "name": "executionContextId", "$ref": "Runtime.ExecutionContextId", "description": "Specifies script creation context." },
                     { "name": "hash", "type": "string", "description": "Content hash of the script."},
                     { "name": "executionContextAuxData", "type": "object", "optional": true, "description": "Embedder-specific auxiliary data." },
                     { "name": "isLiveEdit", "type": "boolean", "optional": true, "description": "True, if this script is generated as a result of the live edit operation.", "experimental": true },
                     { "name": "sourceMapURL", "type": "string", "optional": true, "description": "URL of source map associated with script (if any)." },
                     { "name": "hasSourceURL", "type": "boolean", "optional": true, "description": "True, if this script has sourceURL.", "experimental": true },
                     { "name": "isModule", "type": "boolean", "optional": true, "description": "True, if this script is ES6 module.", "experimental": true },
-                    { "name": "length", "type": "integer", "optional": true, "description": "This script length.", "experimental": true }
+                    { "name": "length", "type": "integer", "optional": true, "description": "This script length.", "experimental": true },
+                    { "name": "stackTrace", "$ref": "Runtime.StackTrace", "optional": true, "description": "JavaScript stack trace if available.", "experimental": true }

[dgozman, 2017/03/16 18:39:03]

- creationStackTrace? evaluationStackTrace?
- please add a meaningful description.

[allada, 2017/03/16 21:02:12]

Per offline comments, I updated description.

                 ],
                 "description": "Fired when virtual machine parses script. This event is also fired for all known and uncollected scripts upon enabling debugger."
             },
             {
                 "name": "scriptFailedToParse",
                 "parameters": [
                     { "name": "scriptId", "$ref": "Runtime.ScriptId", "description": "Identifier of the script parsed." },
                     { "name": "url", "type": "string", "description": "URL or name of the script parsed (if any)." },
                     { "name": "startLine", "type": "integer", "description": "Line offset of the script within the resource with given URL (for script tags)." },
                     { "name": "startColumn", "type": "integer", "description": "Column offset of the script within the resource with given URL." },
@@ skipping 344 matching lines @@
             {
                 "name": "heapStatsUpdate",
                 "description": "If heap objects tracking has been started then backend may send update for one or more fragments",
                 "parameters": [
                     { "name": "statsUpdate", "type": "array", "items": { "type": "integer" }, "description": "An array of triplets. Each triplet describes a fragment. The first integer is the fragment index, the second integer is a total count of objects for the fragment, the third integer is a total size of the objects for the fragment."}
                 ]
             }
         ]
     }]
 }