Fix incorrect setter in current_process_stats_agent.cc.

In my recent change to this file:
https://chromium-review.googlesource.com/c/chromium/src/+/951745/5/remoting/host/current_process_stats_agent.cc#35,
I accidentally called the set_working_set_size setter with the PagefileUsage metric.

This CL fixes it to use the set_pagefile_size setter.

Bug: 819289
Change-Id: I3670f955bb484c1eb27d067c72d17a4d745a2446
TBR: sergeyu@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/953764Reviewed-by: Erik Chen <erikchen@chromium.org>
Reviewed-by: Joe Downing <joedow@chromium.org>
Commit-Queue: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#541642}

remoting/host/current_process_stats_agent.cc

@@ -32,7 +32,7 @@ protocol::ProcessResourceUsage CurrentProcessStatsAgent::GetResourceUsage() {
 #if defined(OS_WIN)
   PROCESS_MEMORY_COUNTERS pmc;
   if (::GetProcessMemoryInfo(::GetCurrentProcess(), &pmc, sizeof(pmc))) {
-    current.set_working_set_size(pmc.PagefileUsage);
+    current.set_pagefile_size(pmc.PagefileUsage);
   }
 #endif