Add {CancelableTaskManager} to handle {Cancelable} concurrent tasks.

src/isolate.cc

 // Copyright 2012 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/isolate.h"
 
 #include <stdlib.h>
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
@@ skipping 1862 matching lines @@
   delete external_reference_table_;
   external_reference_table_ = NULL;
   delete external_reference_map_;
   external_reference_map_ = NULL;
 }
 
 
 void Isolate::Deinit() {
   TRACE_ISOLATE(deinit);
 
+  while (true) {

[Hannes Payer (out of office), 2015/11/04 23:19:00]

Why the while loop?

+    base::LockGuard<base::Mutex> guard(&isolate_mutex_);
+    for (Cancelable* task : cancelable_tasks_) {
+      if (task->CancelForShutdown()) {
+        cancelable_tasks_.erase(task);
+      }
+    }
+    if (cancelable_tasks_.empty()) break;
+  }
+
   debug()->Unload();
 
   FreeThreadResources();
 
   if (concurrent_recompilation_enabled()) {
     optimizing_compile_dispatcher_->Stop();
     delete optimizing_compile_dispatcher_;
     optimizing_compile_dispatcher_ = NULL;
   }
 
@@ skipping 20 matching lines @@
   bootstrapper_->TearDown();
 
   if (runtime_profiler_ != NULL) {
     delete runtime_profiler_;
     runtime_profiler_ = NULL;
   }
 
   delete basic_block_profiler_;
   basic_block_profiler_ = NULL;
 
-  for (Cancelable* task : cancelable_tasks_) {
-    task->Cancel();
-  }
-  cancelable_tasks_.clear();
-
   heap_.TearDown();
   logger_->TearDown();
 
   delete heap_profiler_;
   heap_profiler_ = NULL;
   delete cpu_profiler_;
   cpu_profiler_ = NULL;
 
   delete root_index_map_;
   root_index_map_ = NULL;
@@ skipping 854 matching lines @@
   if (new_length == 0) {
     heap()->set_detached_contexts(heap()->empty_fixed_array());
   } else if (new_length < length) {
     heap()->RightTrimFixedArray<Heap::CONCURRENT_TO_SWEEPER>(
         *detached_contexts, length - new_length);
   }
 }
 
 
 void Isolate::RegisterCancelableTask(Cancelable* task) {
+  base::LockGuard<base::Mutex> guard(&isolate_mutex_);

[Hannes Payer (out of office), 2015/11/04 23:19:00]

Are these methods not always called from the main thread? Why the mutex?

   cancelable_tasks_.insert(task);
 }
 
 
 void Isolate::RemoveCancelableTask(Cancelable* task) {
+  base::LockGuard<base::Mutex> guard(&isolate_mutex_);
   auto removed = cancelable_tasks_.erase(task);
   USE(removed);
   DCHECK(removed == 1);
 }
 
 
 bool StackLimitCheck::JsHasOverflowed(uintptr_t gap) const {
   StackGuard* stack_guard = isolate_->stack_guard();
 #ifdef USE_SIMULATOR
   // The simulator uses a separate JS stack.
@@ skipping 34 matching lines @@
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 }  // namespace internal
 }  // namespace v8