[heap] Reland "Cancel tasks before tearing down the heap."

BUG=chromium:654343

Review-Url: https://codereview.chromium.org/2419783004
Cr-Commit-Position: refs/heads/master@{#40305}

src/cancelable-task.cc

@@ -26,13 +26,15 @@ Cancelable::~Cancelable() {
   }
 }
 
-CancelableTaskManager::CancelableTaskManager() : task_id_counter_(0) {}
+CancelableTaskManager::CancelableTaskManager()
+    : task_id_counter_(0), canceled_(false) {}
 
 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 (cancelable_tasks_.count(id) > 0) ++id;
+  CHECK(!canceled_);
   cancelable_tasks_[id] = task;
   return id;
 }
@@ -69,6 +71,7 @@ void CancelableTaskManager::CancelAndWait() {
   // of canceling we wait for the background tasks that have already been
   // started.
   base::LockGuard<base::Mutex> guard(&mutex_);
+  canceled_ = true;
 
   // Cancelable tasks could be running or could potentially register new
   // tasks, requiring a loop here.

src/cancelable-task.h

@@ -27,6 +27,7 @@ class CancelableTaskManager {
 
   // Registers a new cancelable {task}. Returns the unique {id} of the task that
   // can be used to try to abort a task by calling {Abort}.
+  // Must not be called after CancelAndWait.
   uint32_t Register(Cancelable* task);
 
   // Try to abort running a task identified by {id}. The possible outcomes are:
@@ -40,7 +41,7 @@ class CancelableTaskManager {
   bool TryAbort(uint32_t id);
 
   // Cancels all remaining registered tasks and waits for tasks that are
-  // already running.
+  // already running. This disallows subsequent Register calls.
   void CancelAndWait();
 
  private:
@@ -59,6 +60,8 @@ class CancelableTaskManager {
   base::ConditionVariable cancelable_tasks_barrier_;
   base::Mutex mutex_;
 
+  bool canceled_;
+
   friend class Cancelable;
 
   DISALLOW_COPY_AND_ASSIGN(CancelableTaskManager);

src/isolate.cc

@@ -2227,13 +2227,14 @@ void Isolate::Deinit() {
   delete heap_profiler_;
   heap_profiler_ = NULL;
 
+  cancelable_task_manager()->CancelAndWait();
+
   heap_.TearDown();
   logger_->TearDown();
 
   delete interpreter_;
   interpreter_ = NULL;
 
-  cancelable_task_manager()->CancelAndWait();
 
   delete compiler_dispatcher_tracer_;
   compiler_dispatcher_tracer_ = nullptr;