Update V8 to version 4.1.0.21

This is a cherry-pick of all commits up to and including the
4.1.0.21 cherry-pick in Chromium.

Original commit message:

Version 4.1.0.21 (cherry-pick)

Merged 206e9136bde0f2b5ae8cb77afbb1e7833e5bd412

Unlink pages from the space page list after evacuation.

BUG=430201
LOG=N
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/953813002

Cr-Commit-Position: refs/branch-heads/4.1@{#22}
Cr-Branched-From: 2e08d2a7aa9d65d269d8c57aba82eb38a8cb0a18-refs/heads/candidates@{#25353}

---

FPIIM-449

Change-Id: I8c23c7bbb70772b4858fe8a47b64fa97ee0d1f8c
diff --git a/test/js-perf-test/Collections/weakmap.js b/test/js-perf-test/Collections/weakmap.js
new file mode 100644
index 0000000..9aa265f
--- /dev/null
+++ b/test/js-perf-test/Collections/weakmap.js
@@ -0,0 +1,79 @@
+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+
+var MapBenchmark = new BenchmarkSuite('WeakMap', [1000], [
+  new Benchmark('Set', false, false, 0, WeakMapSet, WeakMapSetupBase,
+      WeakMapTearDown),
+  new Benchmark('Has', false, false, 0, WeakMapHas, WeakMapSetup,
+      WeakMapTearDown),
+  new Benchmark('Get', false, false, 0, WeakMapGet, WeakMapSetup,
+      WeakMapTearDown),
+  new Benchmark('Delete', false, false, 0, WeakMapDelete, WeakMapSetup,
+      WeakMapTearDown),
+]);
+
+
+var wm;
+
+
+function WeakMapSetupBase() {
+  SetupObjectKeys();
+  wm = new WeakMap;
+}
+
+
+function WeakMapSetup() {
+  WeakMapSetupBase();
+  WeakMapSet();
+}
+
+
+function WeakMapTearDown() {
+  wm = null;
+}
+
+
+function WeakMapSet() {
+  for (var i = 0; i < N; i++) {
+    wm.set(keys[i], i);
+  }
+}
+
+
+function WeakMapHas() {
+  for (var i = 0; i < N; i++) {
+    if (!wm.has(keys[i])) {
+      throw new Error();
+    }
+  }
+  for (var i = N; i < 2 * N; i++) {
+    if (wm.has(keys[i])) {
+      throw new Error();
+    }
+  }
+}
+
+
+function WeakMapGet() {
+  for (var i = 0; i < N; i++) {
+    if (wm.get(keys[i]) !== i) {
+      throw new Error();
+    }
+  }
+  for (var i = N; i < 2 * N; i++) {
+    if (wm.get(keys[i]) !== undefined) {
+      throw new Error();
+    }
+  }
+}
+
+
+function WeakMapDelete() {
+  // This is run more than once per setup so we will end up deleting items
+  // more than once. Therefore, we do not the return value of delete.
+  for (var i = 0; i < N; i++) {
+    wm.delete(keys[i]);
+  }
+}