Factor out arch-independent ScaleFactor definition.

Bug: 65872996
Test: m test-art-host-gtest
Test: art/test.py --host -r --optimizing
Change-Id: I27763286847b45a5a3a493c3dba48418575b3eb6
diff --git a/compiler/optimizing/code_generator.h b/compiler/optimizing/code_generator.h
index 338aac0..99de61d 100644
--- a/compiler/optimizing/code_generator.h
+++ b/compiler/optimizing/code_generator.h
@@ -36,6 +36,7 @@
 #include "optimizing_compiler_stats.h"
 #include "read_barrier_option.h"
 #include "stack.h"
+#include "utils/assembler.h"
 #include "utils/label.h"
 
 namespace art {
@@ -701,6 +702,7 @@
   virtual void GenerateNop() = 0;
 
   static QuickEntrypointEnum GetArrayAllocationEntrypoint(HNewArray* new_array);
+  static ScaleFactor ScaleFactorForType(DataType::Type type);
 
  protected:
   // Patch info used for recording locations of required linker patches and their targets,