Disable WindowCapturer tests on OSX and Linux

R=alexeypa@chromium.org

Review URL: https://webrtc-codereview.appspot.com/1533004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@4085 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/modules/desktop_capture/window_capturer_unittest.cc b/modules/desktop_capture/window_capturer_unittest.cc
index 6f75f21..c3b15fe 100644
--- a/modules/desktop_capture/window_capturer_unittest.cc
+++ b/modules/desktop_capture/window_capturer_unittest.cc
@@ -42,6 +42,8 @@
   scoped_ptr<DesktopFrame> frame_;
 };
 
+#if defined(WEBRTC_WIN)
+
 // Verify that we can enumerate windows.
 TEST_F(WindowCapturerTest, Enumerate) {
   WindowCapturer::WindowList windows;
@@ -93,4 +95,6 @@
   }
 }
 
+#endif  // defined(WEBRTC_WIN)
+
 }  // namespace webrtc