Added tracking of memory usage within ApiNativeScopes. Usage to be displayed within Observatory.

runtime/vm/zone_test.cc

 // Copyright (c) 2012, 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/assert.h"
 #include "vm/dart.h"
 #include "vm/isolate.h"
 #include "vm/unit_test.h"
 #include "vm/zone.h"
 
@@ skipping 210 matching lines @@
                       zone.CapacityInBytes(), zone.SizeInBytes());
       EXPECT_LE(zone.SizeInBytes(), zone.CapacityInBytes());
       EXPECT_SUBSTRING(size_buf, json);
     }
   }
   EXPECT(thread->zone() == NULL);
   Dart_ShutdownIsolate();
 }
 #endif
 
+
+UNIT_TEST_CASE(NativeScopeZoneAllocation) {
+  ASSERT(ApiNativeScope::Current() == NULL);
+  ASSERT(Thread::Current() == NULL);
+  EXPECT_EQ(0, ApiNativeScope::current_memory_usage());
+  {
+    ApiNativeScope scope;
+    EXPECT_EQ(scope.zone()->CapacityInBytes(),
+              ApiNativeScope::current_memory_usage());
+    (void)Dart_ScopeAllocate(2048);
+    EXPECT_EQ(scope.zone()->CapacityInBytes(),
+              ApiNativeScope::current_memory_usage());
+  }
+  EXPECT_EQ(0, ApiNativeScope::current_memory_usage());
+}
+
 }  // namespace dart