Bug 1620630 - The OS.File worker should record markers indicating which operation it is performing on which file, r=Yoric.

Differential Revision: https://phabricator.services.mozilla.com/D65747

--HG--
extra : moz-landing-system : lando

services/settings/test/unit/test_attachments_downloader.js

@@ -192,7 +192,11 @@ add_task(async function test_delete_removes_local_file() {
   downloader.delete(RECORD);
 
   Assert.ok(!(await OS.File.exists(localFilePath)));
-  Assert.ok(!(await OS.File.exists(downloader.baseFolder)));
+  Assert.ok(
+    !(await OS.File.exists(
+      OS.Path.join(OS.Constants.Path.localProfileDir, ...downloader.folders)
+    ))
+  );
 });
 add_task(clear_state);
 

toolkit/components/osfile/modules/osfile_async_worker.js

@@ -29,7 +29,23 @@ if (this.Components) {
 
   let worker = new PromiseWorker.AbstractWorker();
   worker.dispatch = function(method, args = []) {
-    return Agent[method](...args);
+    let prefix = "OS.File " + method;
+    performance.mark(prefix + "-start");
+    try {
+      return Agent[method](...args);
+    } finally {
+      let name = prefix;
+      if (args.length && args[0] instanceof Object && args[0].string) {
+        // Including the path in the marker name here means it will be part of
+        // profiles. It's fine to include personally identifiable information
+        // in profiles, because when a profile is captured only the user will
+        // see it, and before uploading it a sanitization step will be offered.
+        // The 'OS.File ' prefix will help the profiler know that these marker
+        // names should be sanitized.
+        name += " — " + args[0].string;
+      }
+      performance.measure(name, prefix + "-start");
+    }
   };
   worker.log = LOG;
   worker.postMessage = function(message, ...transfers) {