When an Isolate is configured to use lockers, foreground tasks need to lock

gin/v8_platform.cc

 // Copyright 2014 The Chromium 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 "gin/public/v8_platform.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/sys_info.h"
 #include "base/threading/worker_pool.h"
 #include "base/trace_event/trace_event.h"
 #include "gin/per_isolate_data.h"
 
 namespace gin {
 
 namespace {
 
 base::LazyInstance<V8Platform>::Leaky g_v8_platform = LAZY_INSTANCE_INITIALIZER;
 
+void RunWithLocker(v8::Isolate* isolate, v8::Task* task) {
+  v8::Locker lock(isolate);
+  task->Run();
+}
+
 }  // namespace
 
 // static
 V8Platform* V8Platform::Get() { return g_v8_platform.Pointer(); }
 
 V8Platform::V8Platform() {}
 
 V8Platform::~V8Platform() {}
 
 size_t V8Platform::NumberOfAvailableBackgroundThreads() {
@@ skipping 12 matching lines @@
 void V8Platform::CallOnBackgroundThread(
     v8::Task* task,
     v8::Platform::ExpectedRuntime expected_runtime) {
   base::WorkerPool::PostTask(
       FROM_HERE,
       base::Bind(&v8::Task::Run, base::Owned(task)),
       expected_runtime == v8::Platform::kLongRunningTask);
 }
 
 void V8Platform::CallOnForegroundThread(v8::Isolate* isolate, v8::Task* task) {
-  PerIsolateData::From(isolate)->task_runner()->PostTask(
-      FROM_HERE, base::Bind(&v8::Task::Run, base::Owned(task)));
+  PerIsolateData* data = PerIsolateData::From(isolate);

[ulan, 2016/11/04 14:28:30]

The same change should apply to other Call*OnForegroundThread functions?

+  if (data->access_mode() == IsolateHolder::kUseLocker) {
+    data->task_runner()->PostTask(
+        FROM_HERE, base::Bind(RunWithLocker, base::Unretained(isolate),
+                              base::Owned(task)));
+  } else {
+    data->task_runner()->PostTask(
+        FROM_HERE, base::Bind(&v8::Task::Run, base::Owned(task)));
+  }
 }
 
 void V8Platform::CallDelayedOnForegroundThread(v8::Isolate* isolate,
                                                v8::Task* task,
                                                double delay_in_seconds) {
   PerIsolateData::From(isolate)->task_runner()->PostDelayedTask(
       FROM_HERE, base::Bind(&v8::Task::Run, base::Owned(task)),
       base::TimeDelta::FromSecondsD(delay_in_seconds));
 }
 
@@ skipping 141 matching lines @@
     v8::Platform::TraceStateObserver* observer) {
   g_trace_state_dispatcher.Get().AddObserver(observer);
 }
 
 void V8Platform::RemoveTraceStateObserver(
     v8::Platform::TraceStateObserver* observer) {
   g_trace_state_dispatcher.Get().RemoveObserver(observer);
 }
 
 }  // namespace gin