ART: Add dex::TypeIndex

Add abstraction for uint16_t type index.

Test: m test-art-host
Change-Id: I47708741c7c579cbbe59ab723c1e31c5fe71f83a
diff --git a/runtime/utils/dex_cache_arrays_layout-inl.h b/runtime/utils/dex_cache_arrays_layout-inl.h
index c7875b5..bd1b044 100644
--- a/runtime/utils/dex_cache_arrays_layout-inl.h
+++ b/runtime/utils/dex_cache_arrays_layout-inl.h
@@ -65,8 +65,8 @@
   return PointerSize::k32;
 }
 
-inline size_t DexCacheArraysLayout::TypeOffset(uint32_t type_idx) const {
-  return types_offset_ + ElementOffset(GcRootAsPointerSize<mirror::Class>(), type_idx);
+inline size_t DexCacheArraysLayout::TypeOffset(dex::TypeIndex type_idx) const {
+  return types_offset_ + ElementOffset(GcRootAsPointerSize<mirror::Class>(), type_idx.index_);
 }
 
 inline size_t DexCacheArraysLayout::TypesSize(size_t num_elements) const {