Improve Windows build instructions

This change removes a stray reference to VS 2015, clarifies when VS
2017 became required, and clarifies which VS 2017 components must be
installed.

Bug: 699375
Change-Id: Ia06240a4581afb784a25330170c61ce3f124cf17
Reviewed-on: https://chromium-review.googlesource.com/724284
Commit-Queue: Bruce Dawson <brucedawson@chromium.org>
Reviewed-by: Victor Costan <pwnall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#509631}

docs/windows_build_instructions.md

@@ -16,19 +16,21 @@ Are you a Google employee? See
   recommended.
 * At least 100GB of free disk space on an NTFS-formatted hard drive. FAT32
   will not work, as some of the Git packfiles are larger than 4GB.
-* Visual Studio 2015 Update 3, see below (no other version is supported).
+* An appropriate version of Visual Studio, as described below.
 * Windows 7 or newer.
 
 ## Setting up Windows
 
 ### Visual Studio
 
-As of September, 2017 Chromium requires Visual Studio 2017 update 3.2 with the
-15063 (Creators Update) Windows SDK or later to build. Visual Studio Community
-Edition should work if its license is appropriate for you. You must install the
-VC++ toolchain and MFC. This can be done from the command line like this:
+As of September, 2017 (R503915) Chromium requires Visual Studio 2017 update 3.2
+with the 15063 (Creators Update) Windows SDK or later to build. Visual Studio
+Community Edition should work if its license is appropriate for you. You must
+install the "Desktop development with C++" component and the "MFC and ATL
+support" sub-component. This can be done from the command line by passing these
+arguments to the Visual Studio installer that you download:
 ```shell
-vs_professional.exe --add Microsoft.VisualStudio.Workload.NativeDesktop
+--add Microsoft.VisualStudio.Workload.NativeDesktop
     --add Microsoft.VisualStudio.Component.VC.ATLMFC --includeRecommended
 ```
 You must have the Windows 10 SDK installed, version 10.0.15063 or later.