Add support for building targets directly from gyp.

test/lib/TestGyp.py

Index: test/lib/TestGyp.py
diff --git a/test/lib/TestGyp.py b/test/lib/TestGyp.py
index 64edafa49259faef0446e8291316317d43b6467c..a36ab9a9571e84c4ba3a97a779ee046966f34c8e 100644
--- a/test/lib/TestGyp.py
+++ b/test/lib/TestGyp.py
@@ -604,6 +604,14 @@ class TestGypMake(TestGypBase):
     return self.workpath(*result)
 
 
+def ConvertToCygpath(path):
+  """Convert to cygwin path if we are using cygwin."""
+  if sys.platform == 'cygwin':
+    p = subprocess.Popen(['cygpath', path], stdout=subprocess.PIPE)
+    path = p.communicate()[0].strip()
+  return path
+
+
 def FindVisualStudioInstallation():
   """Returns appropriate values for .build_tool and .uses_msbuild fields
   of TestGypBase for Visual Studio.
@@ -619,6 +627,8 @@ def FindVisualStudioInstallation():
       '2008': r'Microsoft Visual Studio 9.0\Common7\IDE\devenv.com',
       '2005': r'Microsoft Visual Studio 8\Common7\IDE\devenv.com'}
 
+  possible_roots = [ConvertToCygpath(r) for r in possible_roots]
+
   msvs_version = 'auto'
   for flag in (f for f in sys.argv if f.startswith('msvs_version=')):
     msvs_version = flag.split('=')[-1]