Add TaskPriority as a parameter to SequencedWorkerPool in preparation for TaskScheduler experiment.

net/proxy/dhcp_proxy_script_fetcher_win.cc

Index: net/proxy/dhcp_proxy_script_fetcher_win.cc
diff --git a/net/proxy/dhcp_proxy_script_fetcher_win.cc b/net/proxy/dhcp_proxy_script_fetcher_win.cc
index 87006114929f37083984c0991accf92d5142edb5..cb95ad5aeb873ca449e8aa9aa61304b4282f2e5f 100644
--- a/net/proxy/dhcp_proxy_script_fetcher_win.cc
+++ b/net/proxy/dhcp_proxy_script_fetcher_win.cc
@@ -58,8 +58,9 @@ DhcpProxyScriptFetcherWin::DhcpProxyScriptFetcherWin(
       url_request_context_(url_request_context) {
   DCHECK(url_request_context_);
 
-  worker_pool_ = new base::SequencedWorkerPool(kMaxDhcpLookupThreads,
-                                               "PacDhcpLookup");
+  worker_pool_ =
+      new base::SequencedWorkerPool(kMaxDhcpLookupThreads, "PacDhcpLookup",

[eroman, 2016/06/23 01:19:21]

BTW I don't believe this actually has any ordering requirements.

Looks like it is just using the maximum threads parameter to rate limit the
requests made, could be changed to ExecutionMode:PARALLEL in the future.

[gab, 2016/06/27 21:29:32]

Ack, will keep in mind for later, thanks!

+                                    base::TaskPriority::USER_BLOCKING);

[eroman, 2016/06/23 01:19:21]

USER_VISIBLE should be good enough for this.

As an aside, I wonder if just these 3 priority classes will be sufficiently
granular to make good scheduling choices.

Here for instance after the transition we could just be firing off all the tasks
with ExecutionMode::PARALLEL and priority=USER_VISIBLE.

That is fine, but in theory we have more information available. Some of the
tasks (adapter probes) are less important than others and could be
de-prioritized. But not so unimportant as to become BACKGROUND.

This particular case isn't all that interesting (wasn't really optimized
before), but still curious if there are plans to have more priorities or other
ways to describe precedence of tasks than those 3.

[gab, 2016/06/27 21:29:32]

Done.
Interesting, filed http://crbug.com/623683 to consider this.

 }
 
 DhcpProxyScriptFetcherWin::~DhcpProxyScriptFetcherWin() {