[turbofan] Minor cleanup for JSGenericLowering.

src/compiler/js-generic-lowering.cc

Index: src/compiler/js-generic-lowering.cc
diff --git a/src/compiler/js-generic-lowering.cc b/src/compiler/js-generic-lowering.cc
index 42c5e56dce46e3fa7451fe5c1412a46f044170b1..d1b06ed5ba6b2719bbb5c6412009aadff2866ef1 100644
--- a/src/compiler/js-generic-lowering.cc
+++ b/src/compiler/js-generic-lowering.cc
@@ -6,6 +6,7 @@
 #include "src/code-stubs.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/js-generic-lowering.h"
+#include "src/compiler/js-graph.h"
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
@@ -20,6 +21,9 @@ JSGenericLowering::JSGenericLowering(bool is_typing_enabled, JSGraph* jsgraph)
     : is_typing_enabled_(is_typing_enabled), jsgraph_(jsgraph) {}
 
 
+JSGenericLowering::~JSGenericLowering() {}
+
+
 Reduction JSGenericLowering::Reduce(Node* node) {
   switch (node->opcode()) {
 #define DECLARE_CASE(x)  \
@@ -514,6 +518,25 @@ void JSGenericLowering::LowerJSStackCheck(Node* node) {
   ReplaceWithRuntimeCall(node, Runtime::kStackGuard);
 }
 
+
+Zone* JSGenericLowering::zone() const { return graph()->zone(); }
+
+
+Isolate* JSGenericLowering::isolate() const { return jsgraph()->isolate(); }
+
+
+Graph* JSGenericLowering::graph() const { return jsgraph()->graph(); }
+
+
+CommonOperatorBuilder* JSGenericLowering::common() const {
+  return jsgraph()->common();
+}
+
+
+MachineOperatorBuilder* JSGenericLowering::machine() const {
+  return jsgraph()->machine();
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8