Introduce a class encapsulating arguments descriptor arrays.

runtime/vm/code_patcher_ia32_test.cc

Index: runtime/vm/code_patcher_ia32_test.cc
diff --git a/runtime/vm/code_patcher_ia32_test.cc b/runtime/vm/code_patcher_ia32_test.cc
index f88550d557e5d00792ad525612d330f4183e4e3f..72b44dd925a0a1c0abcf0192c6c43cfacd04231d 100644
--- a/runtime/vm/code_patcher_ia32_test.cc
+++ b/runtime/vm/code_patcher_ia32_test.cc
@@ -56,11 +56,13 @@ ASSEMBLER_TEST_GENERATE(IcDataAccess, assembler) {
                     true, false, false, false, owner_class, 0));
 
   const String& target_name = String::Handle(String::New("targetFunction"));
-  ICData& ic_data = ICData::ZoneHandle(
-      ICData::New(function, target_name, 15, 1));
+  const ICData& ic_data =
+      ICData::ZoneHandle(ICData::New(function, target_name, 15, 1));
+  const Array& arg_descriptor =
+      Array::ZoneHandle(ArgumentsDescriptor::New(1, Array::Handle()));
 
   __ LoadObject(ECX, ic_data);
-  __ LoadObject(EDX, DartEntry::ArgumentsDescriptor(1, Array::Handle()));
+  __ LoadObject(EDX, arg_descriptor);
   ExternalLabel target_label(
       "InlineCache", StubCode::OneArgCheckInlineCacheEntryPoint());
   __ call(&target_label);