Teach the Observatory about Contexts. Factor out object graph information from the instance view.

runtime/bin/vmservice/observatory/lib/src/elements/context_ref.html

Index: runtime/bin/vmservice/observatory/lib/src/elements/context_ref.html
diff --git a/runtime/bin/vmservice/observatory/lib/src/elements/context_ref.html b/runtime/bin/vmservice/observatory/lib/src/elements/context_ref.html
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index 0000000000000000000000000000000000000000..756cb80490ec1d6c68a6569b7fd5f0a2b9235079
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@@ -0,0 +1,33 @@
+<link rel="import" href="../../../../packages/polymer/polymer.html">
+<link rel="import" href="curly_block.html">
+<link rel="import" href="observatory_element.html">
+<link rel="import" href="service_ref.html">
+
+<polymer-element name="context-ref" extends="service-ref">
+  <template>
+    <link rel="stylesheet" href="css/shared.css">
+    <span>
+      <a on-click="{{ goto }}" _href="{{ url }}"><em>Context</em> ({{ ref.length }})</a>
+      <curly-block callback="{{ expander() }}">
+        <div class="memberList">
+          <div class="memberItem">
+            <div class="memberName">parent</div>
+            <div class="memberValue">
+              <any-service-ref ref="{{ ref.parentContext }}"></any-service-ref>
+            </div>
+          </div>
+          <template repeat="{{ element in ref.elements }}">
+            <div class="memberItem">
+              <div class="memberName">[{{ element['index']}}]</div>
+              <div class="memberValue">
+                <any-service-ref ref="{{ element['value'] }}"></any-service-ref>
+              </div>
+            </div>
+          </template>
+        </div>
+      </curly-block>
+    </span>
+  </template>
+</polymer-element>
+
+<script type="application/dart" src="context_ref.dart"></script>