gyp: apply https://codereview.chromium.org/11361103/

gyp/pylib/gyp/generator/msvs.py

@@ -2612,6 +2612,9 @@ def _GetMSBuildAttributes(spec, config, build_file):
     product_name = spec.get('product_name', '$(ProjectName)')
     target_name = prefix + product_name
     msbuild_attributes['TargetName'] = target_name
+  if 'TargetExt' not in msbuild_attributes and 'product_extension' in spec:
+    ext = spec.get('product_extension')
+    msbuild_attributes['TargetExt'] = '.' + ext
 
   # Make sure that 'TargetPath' matches 'Lib.OutputFile' or 'Link.OutputFile'
   # (depending on the tool used) to avoid MSB8012 warning.
@@ -2658,6 +2661,9 @@ def _GetMSBuildConfigurationGlobalProperties(spec, configurations, build_file):
                             attributes['OutputDirectory'])
     _AddConditionalProperty(properties, condition, 'TargetName',
                             attributes['TargetName'])
+    if 'TargetExt' in attributes:
+      _AddConditionalProperty(properties, condition, 'TargetExt',
+                              attributes['TargetExt'])
 
     if attributes.get('TargetPath'):
       _AddConditionalProperty(properties, condition, 'TargetPath',