ART: Add dex::ProtoIndex

Test: m -j32 test-art-host
Change-Id: Ic2d2a7a43be1b8590b97cdf3729200b043ffc6a3
diff --git a/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc b/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
index 39429c5..7e3c3db 100644
--- a/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
+++ b/runtime/entrypoints/quick/quick_trampoline_entrypoints.cc
@@ -2766,7 +2766,7 @@
   const Instruction& inst = caller_method->DexInstructions().InstructionAt(dex_pc);
   DCHECK(inst.Opcode() == Instruction::INVOKE_POLYMORPHIC ||
          inst.Opcode() == Instruction::INVOKE_POLYMORPHIC_RANGE);
-  const uint32_t proto_idx = inst.VRegH();
+  const dex::ProtoIndex proto_idx(inst.VRegH());
   const char* shorty = caller_method->GetDexFile()->GetShorty(proto_idx);
   const size_t shorty_length = strlen(shorty);
   static const bool kMethodIsStatic = false;  // invoke() and invokeExact() are not static.