[stubs] Introduce a dedicated FastNewObjectStub.

src/interface-descriptors.h

Index: src/interface-descriptors.h
diff --git a/src/interface-descriptors.h b/src/interface-descriptors.h
index a713c36a08c97ec135e58835f47b2beb7aeddacd..fb1969d8ef7d27979557581339145dd28371c197 100644
--- a/src/interface-descriptors.h
+++ b/src/interface-descriptors.h
@@ -25,6 +25,7 @@ class PlatformInterfaceDescriptor;
   V(LoadWithVector)                           \
   V(FastNewClosure)                           \
   V(FastNewContext)                           \
+  V(FastNewObject)                            \
   V(FastNewRestParameter)                     \
   V(FastNewSloppyArguments)                   \
   V(FastNewStrictArguments)                   \
@@ -374,6 +375,11 @@ class FastNewContextDescriptor : public CallInterfaceDescriptor {
   DECLARE_DESCRIPTOR(FastNewContextDescriptor, CallInterfaceDescriptor)
 };
 
+class FastNewObjectDescriptor : public CallInterfaceDescriptor {
+ public:
+  DECLARE_DESCRIPTOR(FastNewObjectDescriptor, CallInterfaceDescriptor)
+};
+
 class FastNewRestParameterDescriptor : public CallInterfaceDescriptor {
  public:
   DECLARE_DESCRIPTOR(FastNewRestParameterDescriptor, CallInterfaceDescriptor)