ART: Add dex::TypeIndex

Add abstraction for uint16_t type index.

Test: m test-art-host
Change-Id: I47708741c7c579cbbe59ab723c1e31c5fe71f83a
diff --git a/runtime/art_method.cc b/runtime/art_method.cc
index c550a1b..1c83766 100644
--- a/runtime/art_method.cc
+++ b/runtime/art_method.cc
@@ -199,9 +199,9 @@
   // Iterate over the catch handlers associated with dex_pc.
   PointerSize pointer_size = Runtime::Current()->GetClassLinker()->GetImagePointerSize();
   for (CatchHandlerIterator it(*code_item, dex_pc); it.HasNext(); it.Next()) {
-    uint16_t iter_type_idx = it.GetHandlerTypeIndex();
+    dex::TypeIndex iter_type_idx = it.GetHandlerTypeIndex();
     // Catch all case
-    if (iter_type_idx == DexFile::kDexNoIndex16) {
+    if (!iter_type_idx.IsValid()) {
       found_dex_pc = it.GetHandlerAddress();
       break;
     }