import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

devtools/shared/heapsnapshot/tests/unit/test_HeapSnapshot_creationTime_01.js

@@ -0,0 +1,30 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+// HeapSnapshot.prototype.creationTime returns the expected time.
+
+function waitForThirtyMilliseconds() {
+  const start = Date.now();
+  while (Date.now() - start < 30) ;
+}
+
+function run_test() {
+  const start = Date.now() * 1000;
+  do_print("start                 = " + start);
+
+  // Because Date.now() is less precise than the snapshot's time stamp, give it
+  // a little bit of head room. Additionally, WinXP's timer only has granularity
+  // of +/- 15ms.
+  waitForThirtyMilliseconds();
+  const path = ChromeUtils.saveHeapSnapshot({ runtime: true });
+  waitForThirtyMilliseconds();
+
+  const end = Date.now() * 1000;
+  do_print("end                   = " + end);
+
+  const snapshot = ChromeUtils.readHeapSnapshot(path);
+  do_print("snapshot.creationTime = " + snapshot.creationTime);
+
+  ok(snapshot.creationTime >= start);
+  ok(snapshot.creationTime <= end);
+}