Runtime support for Script Group as single module

Also made two other cleanups:
- Changed KernelID/InvokeID into IDBase in class Closure
    Rather than having two fields in class Closure, one of type ScriptKernelID and
    the other InovkeID, use a single field of the common base class IDBase. Added a
    boolean field to indicate whether it is kernel or invoke, since -fno-rtti is on.
- Removed user pointer from CPU closure

Change-Id: I5553f86b2e58325f85649078d48685a38f12d62f
diff --git a/cpu_ref/rsCpuScript.cpp b/cpu_ref/rsCpuScript.cpp
index ae7e597..481c54d 100644
--- a/cpu_ref/rsCpuScript.cpp
+++ b/cpu_ref/rsCpuScript.cpp
@@ -855,6 +855,10 @@
     rsrSetObject(mCtx->getContext(), (rs_object_base *)destPtr, data);
 }
 
+const char* RsdCpuScriptImpl::getFieldName(uint32_t slot) const {
+    return mScriptExec->getFieldName(slot);
+}
+
 RsdCpuScriptImpl::~RsdCpuScriptImpl() {
 #ifndef RS_COMPATIBILITY_LIB
     if (mCompilerDriver) {