scheduler: Implement task observers

content/child/webthread_impl.cc

Index: content/child/webthread_impl.cc
diff --git a/content/child/webthread_impl.cc b/content/child/webthread_impl.cc
index 9b697def31ab4d1f84e3002bc3a5e36bb8244722..2e30a648b80f8a4e5ea38aad65c61c36ea026500 100644
--- a/content/child/webthread_impl.cc
+++ b/content/child/webthread_impl.cc
@@ -43,7 +43,7 @@ void WebThreadBase::addTaskObserver(TaskObserver* observer) {
       std::make_pair(observer, static_cast<TaskObserverAdapter*>(NULL)));
   if (result.second)
     result.first->second = new TaskObserverAdapter(observer);
-  base::MessageLoop::current()->AddTaskObserver(result.first->second);
+  AddTaskObserverInternal(result.first->second);
 }
 
 void WebThreadBase::removeTaskObserver(TaskObserver* observer) {
@@ -51,11 +51,21 @@ void WebThreadBase::removeTaskObserver(TaskObserver* observer) {
   TaskObserverMap::iterator iter = task_observer_map_.find(observer);
   if (iter == task_observer_map_.end())
     return;
-  base::MessageLoop::current()->RemoveTaskObserver(iter->second);
+  RemoveTaskObserverInternal(iter->second);
   delete iter->second;
   task_observer_map_.erase(iter);
 }
 
+void WebThreadBase::AddTaskObserverInternal(
+    base::MessageLoop::TaskObserver* observer) {
+  base::MessageLoop::current()->AddTaskObserver(observer);

[alex clarke (OOO till 29th), 2015/02/13 11:02:07]

Do we need DCHECK(main_thread_checker_.CalledOnValidThread());

+}
+
+void WebThreadBase::RemoveTaskObserverInternal(
+    base::MessageLoop::TaskObserver* observer) {
+  base::MessageLoop::current()->RemoveTaskObserver(observer);
+}
+
 WebThreadImpl::WebThreadImpl(const char* name)
     : thread_(new base::Thread(name)) {
   thread_->Start();
@@ -84,7 +94,9 @@ WebThreadImpl::WebThreadImpl(const char* name)
 // are no reference counter modification like [A] (because task->run() is not
 // executed), so there are no race conditions.
 // See https://crbug.com/390851 for more details.
-static void RunWebThreadTask(scoped_ptr<blink::WebThread::Task> task) {
+//
+// static
+void WebThreadBase::RunWebThreadTask(scoped_ptr<blink::WebThread::Task> task) {
     task->run();
 }