[API] Extend the `SBThreadPlan` interface

Summary:
This patch extends the `SBThreadPlan` to allow retrieving of thread plans
for scripted steps.

Reviewers: labath, zturner, jingham

Reviewed By: jingham

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D53361

llvm-svn: 345247
diff --git a/lldb/source/API/SBThreadPlan.cpp b/lldb/source/API/SBThreadPlan.cpp
index 393abcb..c15c39a 100644
--- a/lldb/source/API/SBThreadPlan.cpp
+++ b/lldb/source/API/SBThreadPlan.cpp
@@ -207,3 +207,13 @@
     return SBThreadPlan();
   }
 }
+
+SBThreadPlan
+SBThreadPlan::QueueThreadPlanForStepScripted(const char *script_class_name) {
+  if (m_opaque_sp) {
+    return SBThreadPlan(m_opaque_sp->GetThread().QueueThreadPlanForStepScripted(
+        false, script_class_name, false));
+  } else {
+    return SBThreadPlan();
+  }
+}