POSIX: add command line option to launch renderers in a wrapper

base/command_line.h

Index: base/command_line.h
diff --git a/base/command_line.h b/base/command_line.h
index 9a02546b204864aa3a9b5631fd56c1f41d1acac3..94992b8638dfb82b17986eb3af05520521e9a1f9 100644
--- a/base/command_line.h
+++ b/base/command_line.h
@@ -114,6 +114,10 @@ class CommandLine {
   void AppendArguments(const CommandLine& other,
                        bool include_program);
 
+  // On POSIX systems it's common to run processes via a wrapper (like
+  // "valgrind" or "gdb --args"). *Note, only availible on POSIX*
+  void PrependWrapper(const std::wstring& wrapper);
+
  private:
   friend class InProcessBrowserTest;