Implement CONST_CLASS in optimizing compiler.

Change-Id: Ia8c8dfbef87cb2f7893bfb6e178466154eec9efd
diff --git a/compiler/optimizing/code_generator_x86_64.h b/compiler/optimizing/code_generator_x86_64.h
index 32d2702..0de3045 100644
--- a/compiler/optimizing/code_generator_x86_64.h
+++ b/compiler/optimizing/code_generator_x86_64.h
@@ -65,6 +65,7 @@
 };
 
 class CodeGeneratorX86_64;
+class SlowPathCodeX86_64;
 
 class ParallelMoveResolverX86_64 : public ParallelMoveResolver {
  public:
@@ -130,6 +131,7 @@
   // is the block to branch to if the suspend check is not needed, and after
   // the suspend call.
   void GenerateSuspendCheck(HSuspendCheck* instruction, HBasicBlock* successor);
+  void GenerateClassInitializationCheck(SlowPathCodeX86_64* slow_path, CpuRegister class_reg);
 
   X86_64Assembler* const assembler_;
   CodeGeneratorX86_64* const codegen_;