Trace key operations

Produce output in Chrome's event tracing format so that it can be viewed
in Chrome/Edge.

src/compiler/commandLineParser.ts

@@ -197,6 +197,14 @@ namespace ts {
             category: Diagnostics.Advanced_Options,
             description: Diagnostics.Generates_a_CPU_profile
         },
+        {
+            name: "generateTrace",
+            type: "string",
+            isFilePath: true,
+            paramType: Diagnostics.FILE_OR_DIRECTORY,
+            category: Diagnostics.Advanced_Options,
+            description: Diagnostics.Generates_an_event_trace_and_a_list_of_types
+        },
         {
             name: "incremental",
             shortName: "i",