Use visual studio toolchain from depot_tools for PDFium compilation

build_gyp/gyp_pdfium

 #!/usr/bin/env python
 #
 # Copyright 2014 PDFium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This script is wrapper for PDFium that adds some support for how GYP
 # is invoked by PDFium beyond what can be done in the gclient hooks.
 
 import os
 import platform
 import sys
 
 script_dir = os.path.dirname(os.path.realpath(__file__))
 pdfium_root = os.path.abspath(os.path.join(script_dir, os.pardir))
+output_rel_dir = 'out'
 
 sys.path.insert(0, os.path.join(pdfium_root, 'tools', 'gyp', 'pylib'))
 import gyp
-
+# vs_toolchain needs to be after gyp path setting since it also uses gyp.
+import vs_toolchain
 
 def run_gyp(args):
   rc = gyp.main(args)
+
+  # Copy Windows toolchain DLLs.
+  vs_runtime_dll_dirs = vs_toolchain.SetEnvironmentAndGetRuntimeDllDirs()
+  if vs_runtime_dll_dirs:
+    x64_runtime, x86_runtime = vs_runtime_dll_dirs
+    vs_toolchain.CopyVsRuntimeDlls(
+      os.path.join(pdfium_root, output_rel_dir), (x86_runtime, x64_runtime))
+
   if rc != 0:
     print 'Error running GYP'
     sys.exit(rc)
 
 
 def main():
   args = sys.argv[1:]
   args.append(os.path.join(pdfium_root, 'build_gyp', 'all.gyp'))
 
   args.append('-I')
   args.append(os.path.join(pdfium_root, 'build_gyp', 'standalone.gypi'))
 
-  args.extend(['-D', 'gyp_output_dir=out'])
+  args.extend(['-D', 'gyp_output_dir=' + output_rel_dir])
 
   # Set the GYP DEPTH variable to the root of the PDFium project.
   args.append('--depth=' + os.path.relpath(pdfium_root))
 
   # GYP does not default to ninja, but PDFium should.
   if not os.environ.get('GYP_GENERATORS', ''):
     print 'GYP_GENERATORS is not set, defaulting to ninja'
     os.environ['GYP_GENERATORS'] = 'ninja'
 
+  # Set up the environment variables.
+  vs_toolchain.SetEnvironmentAndGetRuntimeDllDirs()
+
   print 'Updating projects from gyp files...'
   sys.stdout.flush()
 
   run_gyp(args)
 
 
 if __name__ == '__main__':
   sys.exit(main())