Move logic for site details histograms into MetricsMemoryDetails.

This CL is a refactor with no intended behavior change.

This CL is the beginning of a refactor to separate the two types of consumers of
MemoryDetails:
  * Those that want a human readable string that shows a mapping from [process :
  memory usage].
  * Those that want to emit non-memory related metrics.

Bug: 864352
Change-Id: I0f2a968ef63b3c9fcb658898a2f3f55f68867285
Reviewed-on: https://chromium-review.googlesource.com/1170587
Reviewed-by: Nick Carter <[email protected]>
Reviewed-by: Lei Zhang <[email protected]>
Commit-Queue: Erik Chen <[email protected]>
Cr-Commit-Position: refs/heads/master@{#582243}
diff --git a/chrome/browser/memory_details_win.cc b/chrome/browser/memory_details_win.cc
index 050620d..246ab788 100644
--- a/chrome/browser/memory_details_win.cc
+++ b/chrome/browser/memory_details_win.cc
@@ -2,12 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/browser/memory_details.h"
+// Windows headers must come first.
+#include <windows.h>
 
 #include <psapi.h>
 #include <stddef.h>
 #include <TlHelp32.h>
 
+#include "chrome/browser/memory_details.h"
+
 #include <memory>
 
 #include "base/bind.h"