add memory usage to the diagnostics page

pkg/analysis_server/lib/src/domain_diagnostic.dart

Index: pkg/analysis_server/lib/src/domain_diagnostic.dart
diff --git a/pkg/analysis_server/lib/src/domain_diagnostic.dart b/pkg/analysis_server/lib/src/domain_diagnostic.dart
index 53785fe9ed00619efd0792dfcc79ea00884feec6..8e6027ae202b7b40ac1da68a4d68f76b9f28d3ef 100644
--- a/pkg/analysis_server/lib/src/domain_diagnostic.dart
+++ b/pkg/analysis_server/lib/src/domain_diagnostic.dart
@@ -124,3 +124,11 @@ class DiagnosticDomainHandler implements RequestHandler {
     return null;
   }
 }
+
+class MemoryCpuSample {
+  final DateTime time;
+  final double cpuPercentage;
+  final int memoryKB;
+
+  MemoryCpuSample(this.time, this.cpuPercentage, this.memoryKB);
+}