Adding method to create process using LowBox token in sandbox code.

sandbox/win/src/app_container.h

Index: sandbox/win/src/app_container.h
diff --git a/sandbox/win/src/app_container.h b/sandbox/win/src/app_container.h
index 8125d706fb4addab8d9b43a5db37d723dd9cfaae..a6b2859cfe59766c5347d205e6bbaedfef3ffdfb 100644
--- a/sandbox/win/src/app_container.h
+++ b/sandbox/win/src/app_container.h
@@ -42,6 +42,10 @@ class AppContainerAttributes {
 
   bool HasAppContainer() const;
 
+  // Returns security capabilities structure, which is populated when you call
+  // SetAppContainer.
+  const SECURITY_CAPABILITIES& GetCapabilities() const;
+
  private:
   SECURITY_CAPABILITIES capabilities_;
   std::vector<SID_AND_ATTRIBUTES> attributes_;