Fix some test failures for Windows.

llvm-svn: 223982
diff --git a/lldb/source/Plugins/Process/Windows/ProcessWindows.h b/lldb/source/Plugins/Process/Windows/ProcessWindows.h
index 61afcba..dee8b78 100644
--- a/lldb/source/Plugins/Process/Windows/ProcessWindows.h
+++ b/lldb/source/Plugins/Process/Windows/ProcessWindows.h
@@ -24,6 +24,8 @@
 #include "lldb/Host/HostThread.h"
 #include "lldb/Target/Process.h"
 
+#include "llvm/Support/Mutex.h"
+
 class ProcessMonitor;
 
 namespace lldb_private
@@ -113,6 +115,8 @@
     void OnDebuggerError(const lldb_private::Error &error, uint32_t type) override;
 
   private:
+    llvm::sys::Mutex m_mutex;
+
     // Data for the active debugging session.
     std::unique_ptr<lldb_private::ProcessWindowsData> m_session_data;
 };