Make concrete classes for individual call descriptors.

src/ia32/lithium-ia32.h

Index: src/ia32/lithium-ia32.h
diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
index 1e732322808515c4626bb132b30b3358154f241a..1c24ae7812e370d2f5302b81de4f9bd0269d1b46 100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -1891,10 +1891,10 @@ class LCallJSFunction FINAL : public LTemplateInstruction<1, 1, 0> {
 
 class LCallWithDescriptor FINAL : public LTemplateResultInstruction<1> {
  public:
-  LCallWithDescriptor(const CallInterfaceDescriptor* descriptor,
+  LCallWithDescriptor(CallInterfaceDescriptor descriptor,
                       const ZoneList<LOperand*>& operands, Zone* zone)
-      : inputs_(descriptor->GetRegisterParameterCount() + 1, zone) {
-    DCHECK(descriptor->GetRegisterParameterCount() + 1 == operands.length());
+      : inputs_(descriptor.GetRegisterParameterCount() + 1, zone) {
+    DCHECK(descriptor.GetRegisterParameterCount() + 1 == operands.length());
     inputs_.AddAll(operands, zone);
   }