Use TaskScheduler instead of WorkerPool in polling_proxy_config_service.cc.

net/proxy/polling_proxy_config_service.cc

Index: net/proxy/polling_proxy_config_service.cc
diff --git a/net/proxy/polling_proxy_config_service.cc b/net/proxy/polling_proxy_config_service.cc
index defe507eab01492eb4684d2573986102f43c4f13..af6fc9cb630988cc126c6964e1be0c49f12a6360 100644
--- a/net/proxy/polling_proxy_config_service.cc
+++ b/net/proxy/polling_proxy_config_service.cc
@@ -11,8 +11,8 @@
 #include "base/observer_list.h"
 #include "base/single_thread_task_runner.h"
 #include "base/synchronization/lock.h"
+#include "base/task_scheduler/post_task.h"
 #include "base/threading/thread_task_runner_handle.h"
-#include "base/threading/worker_pool.h"
 #include "net/proxy/proxy_config.h"
 
 namespace net {
@@ -90,17 +90,17 @@ class PollingProxyConfigService::Core
     last_poll_time_ = base::TimeTicks::Now();
     poll_task_outstanding_ = true;
     poll_task_queued_ = false;
-    base::WorkerPool::PostTask(
-        FROM_HERE,
-        base::Bind(&Core::PollOnWorkerThread, this, get_config_func_),
-        true);
+    base::PostTaskWithTraits(
+        FROM_HERE, base::TaskTraits().MayBlock().WithShutdownBehavior(

[xunjieli, 2017/02/10 16:53:32]

Why does this have a "MayBlock()" ?

[fdoray, 2017/02/13 15:56:04]

I assumed that this was blocking since it was done on a separate thread. 

On Windows, the task is
https://cs.chromium.org/chromium/src/net/proxy/proxy_config_service_win.cc?q=...

On iOS, the task is
https://cs.chromium.org/chromium/src/net/proxy/proxy_config_service_ios.cc?ty...

You don't believe that this tasks could block?

Disclaimer: I'm not a net/ expert.

[eroman, 2017/02/13 23:14:52]

Correct. The windows implementation may do file i/o (by virtue of registry
lookups), and even network i/o. Which is unfortunately why we had to move it to
be async on a worker thread.

+                       base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN),
+        base::Bind(&Core::PollAsync, this, get_config_func_));
   }
 
  private:
   friend class base::RefCountedThreadSafe<Core>;
   ~Core() {}
 
-  void PollOnWorkerThread(GetConfigFunction func) {
+  void PollAsync(GetConfigFunction func) {
     ProxyConfig config;
     func(&config);