Use ByteArray's native for Socket and File.

runtime/vm/dart_api_impl_test.cc

Index: runtime/vm/dart_api_impl_test.cc
===================================================================
--- runtime/vm/dart_api_impl_test.cc	(revision 3698)
+++ runtime/vm/dart_api_impl_test.cc	(working copy)
@@ -663,6 +663,30 @@
     Dart_ObjectEquals(e1, e2, &is_equal);
     EXPECT(is_equal);
   }
+
+  uint8_t data[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
+  result = Dart_ListSetAsBytes(obj1, 0, data, 10);
+  EXPECT_VALID(result);
+  for (intptr_t i = 0; i < 10; ++i) {
+    Dart_Handle e = Dart_ListGetAt(obj1, i);
+    int64_t value;
+    result = Dart_IntegerToInt64(e, &value);
+    EXPECT_VALID(result);
+    EXPECT_EQ(i, value);
+  }
+
+  for (intptr_t i = 0; i < 10; ++i) {
+    EXPECT_VALID(Dart_ListSetAt(obj1, i, Dart_NewInteger(10 - i)));
+  }
+  Dart_ListGetAsBytes(obj1, 0, data, 10);
+  for (intptr_t i = 0; i < 10; ++i) {
+    Dart_Handle e = Dart_ListGetAt(obj1, i);
+    EXPECT_VALID(e);
+    int64_t value;
+    result = Dart_IntegerToInt64(e, &value);
+    EXPECT_VALID(result);
+    EXPECT_EQ(10 - i, value);
+  }
 }
 
 #endif