Fix build failure on Linux and BSD by reverting r287597

Linux and BSD builds failing after this changes from rev 287597.

llvm-svn: 287631
diff --git a/lldb/source/Breakpoint/BreakpointIDList.cpp b/lldb/source/Breakpoint/BreakpointIDList.cpp
index 037b03e..0f8a027 100644
--- a/lldb/source/Breakpoint/BreakpointIDList.cpp
+++ b/lldb/source/Breakpoint/BreakpointIDList.cpp
@@ -122,12 +122,13 @@
   llvm::StringRef range_from;
   llvm::StringRef range_to;
   llvm::StringRef current_arg;
+  const size_t num_old_args = old_args.GetArgumentCount();
   std::set<std::string> names_found;
 
-  for (size_t i = 0; i < old_args.size(); ++i) {
+  for (size_t i = 0; i < num_old_args; ++i) {
     bool is_range = false;
 
-    current_arg = old_args[i].ref;
+    current_arg = old_args.GetArgumentAtIndex(i);
     if (!allow_locations && current_arg.contains('.')) {
       result.AppendErrorWithFormat(
           "Breakpoint locations not allowed, saw location: %s.",
@@ -151,17 +152,19 @@
         return;
       } else
         names_found.insert(current_arg);
-    } else if ((i + 2 < old_args.size()) &&
-               BreakpointID::IsRangeIdentifier(old_args[i + 1].ref) &&
+    } else if ((i + 2 < num_old_args) &&
+               BreakpointID::IsRangeIdentifier(
+                   old_args.GetArgumentAtIndex(i + 1)) &&
                BreakpointID::IsValidIDExpression(current_arg) &&
-               BreakpointID::IsValidIDExpression(old_args[i + 2].ref)) {
+               BreakpointID::IsValidIDExpression(
+                   old_args.GetArgumentAtIndex(i + 2))) {
       range_from = current_arg;
-      range_to = old_args[i + 2].ref;
+      range_to = old_args.GetArgumentAtIndex(i + 2);
       is_range = true;
       i = i + 2;
     } else {
       // See if user has specified id.*
-      llvm::StringRef tmp_str = old_args[i].ref;
+      llvm::StringRef tmp_str = old_args.GetArgumentAtIndex(i);
       size_t pos = tmp_str.find('.');
       if (pos != llvm::StringRef::npos) {
         llvm::StringRef bp_id_str = tmp_str.substr(0, pos);