Upgrade V8 to version 4.9.385.28

https://chromium.googlesource.com/v8/v8/+/4.9.385.28

FPIIM-449

Change-Id: I4b2e74289d4bf3667f2f3dc8aa2e541f63e26eb4
diff --git a/src/cancelable-task.cc b/src/cancelable-task.cc
new file mode 100644
index 0000000..d231bb7
--- /dev/null
+++ b/src/cancelable-task.cc
@@ -0,0 +1,123 @@
+// Copyright 2015 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.
+
+#include "src/cancelable-task.h"
+
+#include "src/base/platform/platform.h"
+#include "src/isolate.h"
+
+namespace v8 {
+namespace internal {
+
+
+Cancelable::Cancelable(CancelableTaskManager* parent)
+    : parent_(parent), status_(kWaiting), id_(0), cancel_counter_(0) {
+  id_ = parent->Register(this);
+  CHECK(id_ != 0);
+}
+
+
+Cancelable::~Cancelable() {
+  // The following check is needed to avoid calling an already terminated
+  // manager object. This happens when the manager cancels all pending tasks
+  // in {CancelAndWait} only before destroying the manager object.
+  if (TryRun() || IsRunning()) {
+    parent_->RemoveFinishedTask(id_);
+  }
+}
+
+
+static bool ComparePointers(void* ptr1, void* ptr2) { return ptr1 == ptr2; }
+
+
+CancelableTaskManager::CancelableTaskManager()
+    : task_id_counter_(0), cancelable_tasks_(ComparePointers) {}
+
+
+uint32_t CancelableTaskManager::Register(Cancelable* task) {
+  base::LockGuard<base::Mutex> guard(&mutex_);
+  uint32_t id = ++task_id_counter_;
+  // The loop below is just used when task_id_counter_ overflows.
+  while ((id == 0) || (cancelable_tasks_.Lookup(reinterpret_cast<void*>(id),
+                                                id) != nullptr)) {
+    ++id;
+  }
+  HashMap::Entry* entry =
+      cancelable_tasks_.LookupOrInsert(reinterpret_cast<void*>(id), id);
+  entry->value = task;
+  return id;
+}
+
+
+void CancelableTaskManager::RemoveFinishedTask(uint32_t id) {
+  base::LockGuard<base::Mutex> guard(&mutex_);
+  void* removed = cancelable_tasks_.Remove(reinterpret_cast<void*>(id), id);
+  USE(removed);
+  DCHECK(removed != nullptr);
+  cancelable_tasks_barrier_.NotifyOne();
+}
+
+
+bool CancelableTaskManager::TryAbort(uint32_t id) {
+  base::LockGuard<base::Mutex> guard(&mutex_);
+  HashMap::Entry* entry =
+      cancelable_tasks_.Lookup(reinterpret_cast<void*>(id), id);
+  if (entry != nullptr) {
+    Cancelable* value = reinterpret_cast<Cancelable*>(entry->value);
+    if (value->Cancel()) {
+      // Cannot call RemoveFinishedTask here because of recursive locking.
+      void* removed = cancelable_tasks_.Remove(reinterpret_cast<void*>(id), id);
+      USE(removed);
+      DCHECK(removed != nullptr);
+      cancelable_tasks_barrier_.NotifyOne();
+      return true;
+    }
+  }
+  return false;
+}
+
+
+void CancelableTaskManager::CancelAndWait() {
+  // Clean up all cancelable fore- and background tasks. Tasks are canceled on
+  // the way if possible, i.e., if they have not started yet.  After each round
+  // of canceling we wait for the background tasks that have already been
+  // started.
+  base::LockGuard<base::Mutex> guard(&mutex_);
+
+  // HashMap does not support removing while iterating, hence keep a set of
+  // entries that are to be removed.
+  std::set<uint32_t> to_remove;
+
+  // Cancelable tasks could potentially register new tasks, requiring a loop
+  // here.
+  while (cancelable_tasks_.occupancy() > 0) {
+    for (HashMap::Entry* p = cancelable_tasks_.Start(); p != nullptr;
+         p = cancelable_tasks_.Next(p)) {
+      if (reinterpret_cast<Cancelable*>(p->value)->Cancel()) {
+        to_remove.insert(reinterpret_cast<Cancelable*>(p->value)->id());
+      }
+    }
+    // Remove tasks that were successfully canceled.
+    for (auto id : to_remove) {
+      cancelable_tasks_.Remove(reinterpret_cast<void*>(id), id);
+    }
+    to_remove.clear();
+
+    // Finally, wait for already running background tasks.
+    if (cancelable_tasks_.occupancy() > 0) {
+      cancelable_tasks_barrier_.Wait(&mutex_);
+    }
+  }
+}
+
+
+CancelableTask::CancelableTask(Isolate* isolate)
+    : Cancelable(isolate->cancelable_task_manager()), isolate_(isolate) {}
+
+
+CancelableIdleTask::CancelableIdleTask(Isolate* isolate)
+    : Cancelable(isolate->cancelable_task_manager()), isolate_(isolate) {}
+
+}  // namespace internal
+}  // namespace v8