Use msvs toolchain from depot_tools.

build/gyp_environment.py

 # Copyright 2015 the V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 Sets up various automatic gyp environment variables. These are used by
 gyp_v8 and landmines.py which run at different stages of runhooks. To
 make sure settings are consistent between them, all setup should happen here.
 """
 
 import os
 import sys
+import vs_toolchain
 
 SCRIPT_DIR = os.path.dirname(os.path.realpath(__file__))
 V8_ROOT = os.path.abspath(os.path.join(SCRIPT_DIR, os.pardir))
 
 
 def apply_gyp_environment(file_path=None):
   """
   Reads in a *.gyp_env file and applies the valid keys to os.environ.
   """
   if not file_path or not os.path.exists(file_path):
@@ skipping 20 matching lines @@
         os.environ[var] = val
 
 
 def set_environment():
   """Sets defaults for GYP_* variables."""
 
   if 'SKIP_V8_GYP_ENV' not in os.environ:
     # Update the environment based on v8.gyp_env
     gyp_env_path = os.path.join(os.path.dirname(V8_ROOT), 'v8.gyp_env')
     apply_gyp_environment(gyp_env_path)
+    vs_toolchain.SetEnvironmentAndGetRuntimeDllDirs()