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/mjsunit/es6/debug-stepin-microtasks.js b/test/mjsunit/es6/debug-stepin-microtasks.js
new file mode 100644
index 0000000..8dbdb34
--- /dev/null
+++ b/test/mjsunit/es6/debug-stepin-microtasks.js
@@ -0,0 +1,101 @@
+// 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.
+
+// Flags: --allow-natives-syntax --expose-debug-as debug
+
+Debug = debug.Debug
+var exception = null;
+var break_count = 0;
+var expected_breaks = -1;
+
+function listener(event, exec_state, event_data, data) {
+  try {
+    if (event == Debug.DebugEvent.Break) {
+      assertTrue(exec_state.frameCount() != 0, "FAIL: Empty stack trace");
+      if (!break_count) {
+        // Count number of expected breakpoints in this source file.
+        var source_text = exec_state.frame(0).func().script().source();
+        expected_breaks = source_text.match(/\/\/\s*Break\s+\d+\./g).length;
+        print("Expected breaks: " + expected_breaks);
+      }
+      var source = exec_state.frame(0).sourceLineText();
+      print("paused at: " + source);
+      assertTrue(source.indexOf("// Break " + break_count + ".") > 0,
+                 "Unexpected pause at: " + source + "\n" +
+                 "Expected: // Break " + break_count + ".");
+      if (source.indexOf("StepOver.") !== -1) {
+        exec_state.prepareStep(Debug.StepAction.StepNext, 1);
+      } else {
+        exec_state.prepareStep(Debug.StepAction.StepIn, 1);
+      }
+      ++break_count;
+    }
+  } catch (e) {
+    exception = e;
+    print(e, e.stack);
+  }
+};
+
+Debug.setListener(listener);
+
+Promise.resolve(42)
+  .then(promise1)
+  .then(Object) // Should skip stepping into native.
+  .then(Boolean) // Should skip stepping into native.
+  .then(promise2)
+  .catch(promise3)
+  .catch(function(e) {
+    %AbortJS("FAIL: uncaught exception " + e);
+  });
+
+function promise1() {
+  debugger; // Break 0.
+  return exception || 1; // Break 1.
+} // Break 2.
+
+function promise2() {
+  throw new Error; // Break 3.
+}
+
+function promise3() {
+  installObservers(); // Break 4. StepOver.
+  return break_count; // Break 5.
+} // Break 6.
+
+function installObservers() {
+  var dummy = {};
+  Object.observe(dummy, observer1);
+  Object.observe(dummy, Object); // Should skip stepping into native.
+  Object.observe(dummy, Boolean); // Should skip stepping into native.
+  Object.observe(dummy, observer2);
+  dummy.foo = 1;
+}
+
+function observer1() {
+  return exception || 3; // Break 7.
+} // Break 8.
+
+function observer2() {
+  Promise.resolve().then(promise4); // Break 9. StepOver.
+  return break_count + 1; // Break 10.
+} // Break 11.
+
+function promise4() {
+  finalize(); // Break 12. StepOver.
+  return 0; // Break 13.
+} // Break 14. StepOver.
+
+function finalize() {
+  var dummy = {};
+  Object.observe(dummy, function() {
+    if (expected_breaks !== break_count) {
+      %AbortJS("FAIL: expected <" + expected_breaks + "> breaks instead of <" +
+               break_count + ">");
+    }
+    if (exception !== null) {
+      %AbortJS("FAIL: exception: " + exception);
+    }
+  });
+  dummy.foo = 1;
+}