Revert of Change default Windows compiler to VS 2015

build/toolchain/win/setup_toolchain.py

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 #
 # Copies the given "win tool" (which the toolchain uses to wrap compiler
 # invocations) and the environment blocks for the 32-bit and 64-bit builds on
 # Windows to the build directory.
 #
 # The arguments are the visual studio install location and the location of the
 # win tool. The script assumes that the root build directory is the current dir
@@ skipping 132 matching lines @@
       raise Exception('"%s" failed with error %d' % (args, popen.returncode))
     env = _ExtractImportantEnvironment(variables)
     env['PATH'] = runtime_dirs + ';' + env['PATH']
 
     if cpu == target_cpu:
       for path in env['PATH'].split(os.pathsep):
         if os.path.exists(os.path.join(path, 'cl.exe')):
           vc_bin_dir = os.path.realpath(path)
           break
 
-    # Add extra include directories here that need to be in front of the
-    # installed and packaged include directories. This may be needed in
-    # order to force a particular SDK version, such as to get VS 2013 to use
-    # the Windows 10 SDK. Beware of making the INCLUDE variable excessively
-    # long and be sure to make corresponding changes to build\common.gypi.
-    # Not currently used.
-    #if win_sdk_path:
-    #  additional_includes = ('{sdk_dir}\\Include\\10.0.10586.0\\um;').format(
-    #                              sdk_dir=win_sdk_path)
-    #  env['INCLUDE'] = additional_includes + env['INCLUDE']
+    # The Windows SDK include directories must be first. They both have a sal.h,
+    # and the SDK one is newer and the SDK uses some newer features from it not
+    # present in the Visual Studio one.
+    # Having the Windows SDK first is also the only way to control which SDK
+    # version is used.
+
+    if win_sdk_path:
+      additional_includes = ('{sdk_dir}\\Include\\10.0.10586.0\\shared;' +
+                             '{sdk_dir}\\Include\\10.0.10586.0\\um;' +
+                             '{sdk_dir}\\Include\\10.0.10586.0\\winrt;').format(
+                                  sdk_dir=win_sdk_path)
+      env['INCLUDE'] = additional_includes + env['INCLUDE']
     env_block = _FormatAsEnvironmentBlock(env)
     with open('environment.' + cpu, 'wb') as f:
       f.write(env_block)
 
     # Create a store app version of the environment.
     if 'LIB' in env:
       env['LIB']     = env['LIB']    .replace(r'\VC\LIB', r'\VC\LIB\STORE')
     if 'LIBPATH' in env:
       env['LIBPATH'] = env['LIBPATH'].replace(r'\VC\LIB', r'\VC\LIB\STORE')
     env_block = _FormatAsEnvironmentBlock(env)
     with open('environment.winrt_' + cpu, 'wb') as f:
         f.write(env_block)
 
   assert vc_bin_dir
   print 'vc_bin_dir = "%s"' % vc_bin_dir
 
 
 if __name__ == '__main__':
   main()