[lldb][NFC] Remove ArgEntry::ref member

The StringRef should always be identical to the C string, so we
might as well just create the StringRef from the C-string. This
might be slightly slower until we implement the storage of ArgEntry
with a string instead of a std::unique_ptr<char[]>. Until then we
have to do the additional strlen on the C string to construct the
StringRef.

llvm-svn: 371842
diff --git a/lldb/source/Commands/CommandObjectBreakpoint.cpp b/lldb/source/Commands/CommandObjectBreakpoint.cpp
index 60a5e92..e73c924 100644
--- a/lldb/source/Commands/CommandObjectBreakpoint.cpp
+++ b/lldb/source/Commands/CommandObjectBreakpoint.cpp
@@ -1707,7 +1707,7 @@
     // Make a pass through first to see that all the names are legal.
     for (auto &entry : command.entries()) {
       Status error;
-      if (!BreakpointID::StringIsBreakpointName(entry.ref, error))
+      if (!BreakpointID::StringIsBreakpointName(entry.ref(), error))
       {
         result.AppendErrorWithFormat("Invalid breakpoint name: %s - %s",
                                      entry.c_str(), error.AsCString());