Bug 1705264 [wpt PR 28499] - implement crypto.randomUUID(), a=testonly

Automatic update from web-platform-tests
implement crypto.randomUUID()

Implementation of crypto.randomUUID() using base/guid which indicates
"A cryptographically secure random source will be used".

Refs: https://wicg.github.io/uuid/
Bug: 1197594
Change-Id: I0f5402b4d83a5d89f02425d8050a7737264672dc
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2804758
Commit-Queue: Benjamin Coe <bencoe@google.com>
Reviewed-by: Domenic Denicola <domenic@chromium.org>
Reviewed-by: Mike West <mkwst@chromium.org>
Cr-Commit-Position: refs/heads/master@{#872711}

--

wpt-commits: 15874bf6200f929ecb91726aab4c8e4d1412fee0
wpt-pr: 28499

testing/web-platform/tests/WebCryptoAPI/randomUUID.any.js

@@ -0,0 +1,42 @@
+// Run for enough iterations that we're likely to catch edge-cases, like
+// failing to set a reserved bit:
+const iterations = 256;
+// Track all the UUIDs generated during test run, bail if we ever collide:
+const uuids = new Set()
+function randomUUID() {
+    const uuid = self.crypto.randomUUID();
+    if (uuids.has(uuid)) {
+        throw new Error(`uuid collision ${uuid}`)
+    }
+    uuids.add(uuid);
+    return uuid;
+}
+
+// UUID is in namespace format (16 bytes separated by dashes):
+test(function() {
+    const UUIDRegex = /[a-f0-9]{8}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{4}-[a-f0-9]{12}/
+    for (let i = 0; i < iterations; i++) {
+        assert_true(UUIDRegex.test(randomUUID()));
+    }
+}, "namespace format");
+
+// Set the 4 most significant bits of array[6], which represent the UUID
+// version, to 0b0100:
+test(function() {
+    for (let i = 0; i < iterations; i++) {
+        let value = parseInt(randomUUID().split('-')[2].slice(0, 2), 16);
+        value &= 0b11110000;
+        assert_true(value === 0b01000000);
+    }
+}, "version set");
+
+// Set the 2 most significant bits of array[8], which represent the UUID
+// variant, to 0b10:
+test(function() {
+    for (let i = 0; i < iterations; i++) {
+        // Grab the byte representing array[8]:
+        let value = parseInt(randomUUID().split('-')[3].slice(0, 2), 16);
+        value &= 0b11000000
+        assert_true(value === 0b10000000);
+    }
+}, "variant set");