Factor cpu profile tree into separate element and expose allocation tracing UI

runtime/observatory/lib/src/elements/class_view.dart

Index: runtime/observatory/lib/src/elements/class_view.dart
diff --git a/runtime/observatory/lib/src/elements/class_view.dart b/runtime/observatory/lib/src/elements/class_view.dart
index d839614fa7afbc647dcd35d11e46bfa45303ee46..7ca6fb893215d4d9e2e747986ca1c58ecd3fd845 100644
--- a/runtime/observatory/lib/src/elements/class_view.dart
+++ b/runtime/observatory/lib/src/elements/class_view.dart
@@ -6,6 +6,8 @@ library class_view_element;
 
 import 'dart:async';
 import 'observatory_element.dart';
+import 'package:observatory/cpu_profile.dart';
+import 'package:observatory/elements.dart';
 import 'package:observatory/service.dart';
 import 'package:polymer/polymer.dart';
 
@@ -61,4 +63,24 @@ class ClassViewElement extends ObservatoryElement {
   Future refreshCoverage() {
     return cls.refreshCoverage();
   }
+
+  final CpuProfile profile = new CpuProfile();
+
+  Future refreshAllocationProfile() async {
+    var profileResponse = await cls.getAllocationSamples('UserVM');
+    profile.load(profileResponse.isolate, profileResponse);
+    CpuProfileTreeElement cpuProfileTreeElement =
+        shadowRoot.querySelector('#cpuProfileTree');
+    cpuProfileTreeElement.profile = profile;
+    cpuProfileTreeElement.direction = ProfileTreeDirection.Exclusive;
+    cpuProfileTreeElement.mode = ProfileTreeMode.Function;
+    cpuProfileTreeElement.render();
+  }
+
+  Future toggleAllocationTrace() {
+    if (cls == null) {
+      return new Future(refresh);
+    }
+    return cls.setTraceAllocations(!cls.traceAllocations).whenComplete(refresh);
+  }
 }