Treat null like the object it is in the Observatory and Service.

runtime/vm/service_test.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 
 #include "include/dart_debugger_api.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
@@ skipping 505 matching lines @@
   EXPECT_VALID(valid_id);
   EXPECT_VALID(Dart_SetField(lib, NewString("validId"), valid_id));
 
   Array& service_msg = Array::Handle();
 
   // null
   service_msg = Eval(lib, "[0, port, ['objects', 'null'], [], []]");
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   handler.filterMsg("vmName");
-  EXPECT_STREQ(
+  EXPECT_SUBSTRING(
       "{\"type\":\"Null\",\"id\":\"objects\\/null\","
-      "\"valueAsString\":\"null\"}",
+      "\"valueAsString\":\"null\",\"class\":",
       handler.msg());
 
   // not initialized
   service_msg = Eval(lib, "[0, port, ['objects', 'not-initialized'], [], []]");
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   handler.filterMsg("vmName");
   EXPECT_STREQ(
       "{\"type\":\"Null\",\"id\":\"objects\\/not-initialized\","
       "\"valueAsString\":\"<not initialized>\"}",
@@ skipping 555 matching lines @@
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   ExpectSubstringF(handler.msg(), "\"type\":\"InstanceSet\"");
   ExpectSubstringF(handler.msg(), "\"totalCount\":2");
   ExpectSubstringF(handler.msg(), "\"sampleCount\":2");
   // TODO(koda): Actually parse the response.
   static const intptr_t kInstanceListId = 0;
   ExpectSubstringF(handler.msg(), "\"id\":\"objects\\/%" Pd "\",\"length\":2",
                    kInstanceListId);
   Array& list = Array::Handle();
-  list ^= isolate->object_id_ring()->GetObjectForId(kInstanceListId);
+  ObjectIdRing::LookupResult kind;
+  list ^= isolate->object_id_ring()->GetObjectForId(kInstanceListId, &kind);
   EXPECT_EQ(2, list.Length());
   // The list should contain {b0, b1}.
   EXPECT((list.At(0) == b0.raw() && list.At(1) == b1.raw()) ||
          (list.At(0) == b1.raw() && list.At(1) == b0.raw()));
   // ... and if limit is 1, we one get one of them.
   service_msg = EvalF(lib, "[0, port, ['classes', '%" Pd "', 'instances'],"
                       "['limit'], ['1']]", class_b.id());
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   ExpectSubstringF(handler.msg(), "\"totalCount\":2");
@@ skipping 202 matching lines @@
                 address);
     EXPECT_SUBSTRING(buffer, handler.msg());
   }
 
   // Request native code at address. Expect the null code object back.
   address = last;
   service_msg = EvalF(lib, "[0, port, ['code', 'native-%" Px "'], [], []]",
                       address);
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
-  EXPECT_STREQ("{\"type\":\"Null\",\"id\":\"objects\\/null\","
-               "\"valueAsString\":\"null\"}",
-               handler.msg());
+  EXPECT_SUBSTRING("{\"type\":\"Null\",\"id\":\"objects\\/null\","
+                   "\"valueAsString\":\"null\"",
+                   handler.msg());
 
   // Request malformed native code.
   service_msg = EvalF(lib, "[0, port, ['code', 'native%" Px "'], [], []]",
                       address);
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   EXPECT_SUBSTRING("\"message\":\"Malformed code id:", handler.msg());
 }
 
 
@@ skipping 684 matching lines @@
   service_msg = Eval(lib, "[0, port, ['profile'], ['tags'], ['hidden']]");
   Service::HandleIsolateMessage(isolate, service_msg);
   handler.HandleNextMessage();
   // Expect error.
   EXPECT_SUBSTRING("\"type\":\"Error\"", handler.msg());
 }
 
 #endif  // !defined(TARGET_ARCH_ARM64)
 
 }  // namespace dart