Add the ability to pass extra args to a Python breakpoint callback.

For example, it is pretty easy to write a breakpoint command that implements "stop when my caller is Foo", and
    it is pretty easy to write a breakpoint command that implements "stop when my caller is Bar". But there's no
    way to write a generic "stop when my caller is..." function, and then specify the caller when you add the
    command to a breakpoint.

    With this patch, you can pass this data in a SBStructuredData dictionary. That will get stored in
    the PythonCommandBaton for the breakpoint, and passed to the implementation function (if it has the right
    signature) when the breakpoint is hit. Then in lldb, you can say:

    (lldb) break com add -F caller_is -k caller_name -v Foo

    More generally this will allow us to write reusable Python breakpoint commands.

    Differential Revision: https://reviews.llvm.org/D68671

lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.h

@@ -17,6 +17,7 @@
 
 #include "lldb/Breakpoint/BreakpointOptions.h"
 #include "lldb/Core/IOHandler.h"
+#include "lldb/Core/StructuredDataImpl.h"
 #include "lldb/Interpreter/ScriptInterpreter.h"
 #include "lldb/lldb-private.h"
 
@@ -34,6 +35,13 @@ public:
     CommandDataPython() : BreakpointOptions::CommandData() {
       interpreter = lldb::eScriptLanguagePython;
     }
+    CommandDataPython(StructuredData::ObjectSP extra_args_sp) :
+        BreakpointOptions::CommandData(),
+        m_extra_args_up(new StructuredDataImpl()) {
+        interpreter = lldb::eScriptLanguagePython;
+        m_extra_args_up->SetObjectSP(extra_args_sp);
+    }
+    lldb::StructuredDataImplUP m_extra_args_up;
   };
 
   ScriptInterpreterPython(Debugger &debugger)