Revert of Change the update_client task runner behavior to continue on shutdown.

components/update_client/update_client.cc

Index: components/update_client/update_client.cc
diff --git a/components/update_client/update_client.cc b/components/update_client/update_client.cc
index 497fedb7b8b8b6b450f7d75f38b100d130eed805..ac1ac0559650f1c3154377a56af7966e7cb77952 100644
--- a/components/update_client/update_client.cc
+++ b/components/update_client/update_client.cc
@@ -68,8 +68,7 @@
     scoped_ptr<PingManager> ping_manager,
     UpdateChecker::Factory update_checker_factory,
     CrxDownloader::Factory crx_downloader_factory)
-    : is_stopped_(false),
-      config_(config),
+    : config_(config),
       ping_manager_(ping_manager.Pass()),
       update_engine_(
           new UpdateEngine(config,
@@ -77,13 +76,16 @@
                            crx_downloader_factory,
                            ping_manager_.get(),
                            base::Bind(&UpdateClientImpl::NotifyObservers,
-                                      base::Unretained(this)))) {}
+                                      base::Unretained(this)))) {
+}
 
 UpdateClientImpl::~UpdateClientImpl() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
-  DCHECK(task_queue_.empty());
-  DCHECK(tasks_.empty());
+  while (!task_queue_.empty()) {
+    delete task_queue_.front();
+    task_queue_.pop();
+  }
 
   config_ = nullptr;
 }
@@ -148,16 +150,8 @@
   base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE, base::Bind(completion_callback, error));
 
-  // Remove the task from the set of the running tasks. Only tasks handled by
-  // the update engine can be in this data structure.
   tasks_.erase(task);
-
-  // Delete the completed task. A task can be completed because the update
-  // engine has run it or because it has been canceled but never run.
   delete task;
-
-  if (is_stopped_)
-    return;
 
   // Pick up a task from the queue if the queue has pending tasks and no other
   // task is running.
@@ -201,31 +195,6 @@
   return false;
 }
 
-void UpdateClientImpl::Stop() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-
-  is_stopped_ = true;
-
-  // In the current implementation it is sufficient to cancel the pending
-  // tasks only. The tasks that are run by the update engine will stop
-  // making progress naturally, as the main task runner stops running task
-  // actions. Upon the browser shutdown, the resources employed by the active
-  // tasks will leak, as the operating system kills the thread associated with
-  // the update engine task runner. Further refactoring may be needed in this
-  // area, to cancel the running tasks by canceling the current action update.
-  // This behavior would be expected, correct, and result in no resource leaks
-  // in all cases, in shutdown or not.
-  //
-  // Cancel the pending tasks. These tasks are safe to cancel and delete since
-  // they have not picked up by the update engine, and not shared with any
-  // task runner yet.
-  while (!task_queue_.empty()) {
-    const auto task(task_queue_.front());
-    task_queue_.pop();
-    task->Cancel();
-  }
-}
-
 scoped_refptr<UpdateClient> UpdateClientFactory(
     const scoped_refptr<Configurator>& config) {
   scoped_ptr<PingManager> ping_manager(new PingManager(*config));