Enable stub generation using Hydrogen/Lithium (again)

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index 2faee75843258d14984714cd3ac544fe63c68829..e09f75a97774228e6869ef52636a4ac7a703b03b 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -53,6 +53,7 @@ namespace internal {
 class Bootstrapper;
 class CodeGenerator;
 class CodeRange;
+struct CodeStubInterfaceDescriptor;
 class CompilationCache;
 class ContextSlotCache;
 class ContextSwitcher;
@@ -1062,6 +1063,10 @@ class Isolate {
     date_cache_ = date_cache;
   }
 
+  CodeStubInterfaceDescriptor** code_stub_interface_descriptors() {
+    return code_stub_interface_descriptors_;
+  }
+
   void IterateDeferredHandles(ObjectVisitor* visitor);
   void LinkDeferredHandles(DeferredHandles* deferred_handles);
   void UnlinkDeferredHandles(DeferredHandles* deferred_handles);
@@ -1245,6 +1250,7 @@ class Isolate {
   RegExpStack* regexp_stack_;
   DateCache* date_cache_;
   unibrow::Mapping<unibrow::Ecma262Canonicalize> interp_canonicalize_mapping_;
+  CodeStubInterfaceDescriptor** code_stub_interface_descriptors_;
 
   // The garbage collector should be a little more aggressive when it knows
   // that a context was recently exited.