Use target-specific word instead of runtime word.

Change-Id: Ia11dc3cc520a1a5c7bd017013e5699af9570ce91
diff --git a/compiler/optimizing/code_generator.h b/compiler/optimizing/code_generator.h
index 01bbcc0..e144733 100644
--- a/compiler/optimizing/code_generator.h
+++ b/compiler/optimizing/code_generator.h
@@ -145,6 +145,7 @@
   virtual HGraphVisitor* GetLocationBuilder() = 0;
   virtual HGraphVisitor* GetInstructionVisitor() = 0;
   virtual Assembler* GetAssembler() = 0;
+  virtual size_t GetWordSize() const = 0;
 
   uint32_t GetFrameSize() const { return frame_size_; }
   void SetFrameSize(uint32_t size) { frame_size_ = size; }