Add Support for Visual Studio BuildTools as a possible compiler

Change-Id: I495d0e0a151e6869c2eada7b949fc99c18f85a77
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2232363
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Yngve Pettersen <yngve@vivaldi.com>
Cr-Original-Commit-Position: refs/heads/master@{#775691}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 7b7158d254c13a0390c947ab271df634f4cc9f34

vs_toolchain.py

@@ -164,7 +164,8 @@ def GetVisualStudioVersion():
                               '/Microsoft Visual Studio/%s' % version)
     if path and any(
         os.path.exists(os.path.join(path, edition))
-        for edition in ('Enterprise', 'Professional', 'Community', 'Preview')):
+        for edition in ('Enterprise', 'Professional', 'Community', 'Preview',
+                        'BuildTools')):
       available_versions.append(version)
       break
 
@@ -199,6 +200,9 @@ def DetectVisualStudioPath():
                          version_as_year),
       os.path.expandvars('%ProgramFiles(x86)%' +
                          '/Microsoft Visual Studio/%s/Preview' %
+                         version_as_year),
+      os.path.expandvars('%ProgramFiles(x86)%' +
+                         '/Microsoft Visual Studio/%s/BuildTools' %
                          version_as_year)):
     if path and os.path.exists(path):
       return path