Revert of [refactoring] Split CodeAssemblerState out of CodeAssembler

src/code-stubs-hydrogen.cc

Index: src/code-stubs-hydrogen.cc
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index e080f57a209b04109f8f8477df08beb3e091b17a..790f6879252c26bf37d002f3e7148b33bd4eb833 100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -251,9 +251,8 @@
   const char* name = CodeStub::MajorName(MajorKey());
   Zone zone(isolate()->allocator(), ZONE_NAME);
   CallInterfaceDescriptor interface_descriptor(GetCallInterfaceDescriptor());
-  compiler::CodeAssemblerState state(isolate(), &zone, interface_descriptor,
-                                     GetCodeFlags(), name);
-  CodeStubAssembler assembler(&state);
+  CodeStubAssembler assembler(isolate(), &zone, interface_descriptor,
+                              GetCodeFlags(), name);
   int total_params = interface_descriptor.GetStackParameterCount() +
                      interface_descriptor.GetRegisterParameterCount();
   switch (total_params) {
@@ -285,7 +284,7 @@
       UNIMPLEMENTED();
       break;
   }
-  return compiler::CodeAssembler::GenerateCode(&state);
+  return assembler.GenerateCode();
 }
 
 template <class Stub>