Track live instance and allocation counts for classes

runtime/bin/vmservice/client/lib/src/observatory/application.dart

Index: runtime/bin/vmservice/client/lib/src/observatory/application.dart
diff --git a/runtime/bin/vmservice/client/lib/src/observatory/application.dart b/runtime/bin/vmservice/client/lib/src/observatory/application.dart
index 21eae05e246c9a5656f24f803fbefecece91f62e..1c491ea14dbe9a7778156d3064fde3f450d375fa 100644
--- a/runtime/bin/vmservice/client/lib/src/observatory/application.dart
+++ b/runtime/bin/vmservice/client/lib/src/observatory/application.dart
@@ -50,4 +50,22 @@ class ObservatoryApplication extends Observable {
     }
     return isolate.name;
   }
+
+  static const int KB = 1024;
+  static const int MB = KB * 1024;
+  static String scaledSizeUnits(int x) {
+    if (x > 2 * MB) {
+      var y = x / MB;
+      return '${y.toStringAsFixed(1)} MB';
+    } else if (x > 2 * KB) {
+      var y = x / KB;
+      return '${y.toStringAsFixed(1)} KB';
+    }
+    var y = x.toDouble();
+    return '${y.toStringAsFixed(1)} B';
+  }
+
+  static String timeUnits(double x) {
+    return x.toStringAsFixed(4);
+  }
 }