Using Windows SDK v7.1 when building in MSBuild (Visual Studio 2010/2010e).

build/common.gypi

 # Copyright (c) 2012 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 670 matching lines @@
     'java_bridge%': 0,
 
     # This flag is only used when disable_nacl==0 and disables all those
     # subcomponents which would require the installation of a native_client
     # untrusted toolchain.
     'disable_nacl_untrusted%': 0,
 
     # Disable Dart by default.
     'enable_dart%': 0,
 
+    # The desired version of Windows SDK can be set in ~/.gyp/include.gypi.
+    'msbuild_toolset%': '',
+
     'conditions': [
       # Used to disable Native Client at compile time, for platforms where it
       # isn't supported (ARM)
       ['target_arch=="arm" and chromeos == 1', {
         'disable_nacl%': 1,
        }, {
         'disable_nacl%': 0,
       }],
       ['os_posix==1 and OS!="mac" and OS!="android"', {
         # This will set gcc_version to XY if you are running gcc X.Y.*.
@@ skipping 331 matching lines @@
           'win_release_RuntimeLibrary%': '2', # 2 = /MT (nondebug DLL)
           'win_debug_RuntimeLibrary%': '3',   # 3 = /MTd (debug DLL)
         }, {
           # See http://msdn.microsoft.com/en-us/library/aa652367.aspx
           'win_release_RuntimeLibrary%': '0', # 0 = /MT (nondebug static)
           'win_debug_RuntimeLibrary%': '1',   # 1 = /MTd (debug static)
         }],
       ],
     },
     'conditions': [
+      ['OS=="win" and "<(msbuild_toolset)"!=""', {
+        'msbuild_toolset': '<(msbuild_toolset)',
+      }],
       ['branding=="Chrome"', {
         'defines': ['GOOGLE_CHROME_BUILD'],
       }, {  # else: branding!="Chrome"
         'defines': ['CHROMIUM_BUILD'],
       }],
       ['component=="shared_library"', {
         'defines': ['COMPONENT_BUILD'],
       }],
       ['component=="shared_library" and incremental_chrome_dll==1', {
         # TODO(dpranke): We can't incrementally link chrome when
@@ skipping 1756 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }