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

runtime/bin/vmservice/observatory/test/contexts_test.dart

Index: runtime/bin/vmservice/observatory/test/contexts_test.dart
diff --git a/runtime/bin/vmservice/observatory/test/contexts_test.dart b/runtime/bin/vmservice/observatory/test/contexts_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..47c04415433c5ed71c195941935b3ab63b5f0218
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+++ b/runtime/bin/vmservice/observatory/test/contexts_test.dart
@@ -0,0 +1,119 @@
+// Copyright (c) 2014, 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.
+
+library inbound_references_test;
+
+import 'dart:async';
+import 'package:observatory/service_io.dart';
+import 'package:unittest/unittest.dart';
+import 'test_helper.dart';
+
+var cleanBlock, copyingBlock, fullBlock, fullBlockWithChain;
+
+Function genCleanBlock() {
+  block(x) => x;
+  return block;
+}
+
+Function genCopyingBlock() {
+  final x = 'I could be copied into the block';
+  block() => x;
+  return block;
+}
+
+Function genFullBlock() {
+  var x = 42;  // I must captured in a context.
+  block() => x;
+  x++;
+  return block;
+}
+
+Function genFullBlockWithChain() {
+  var x = 420;  // I must captured in a context.
+  outerBlock() {
+    var y = 4200;
+    innerBlock() => x + y;
+    y++;
+    return innerBlock;
+  }
+  x++;
+  return outerBlock();
+}
+
+void script() {
+  cleanBlock = genCleanBlock();
+  copyingBlock = genCopyingBlock();
+  fullBlock = genFullBlock();
+  fullBlockWithChain = genFullBlockWithChain();
+}
+
+var tests = [
+
+(Isolate isolate) =>
+  isolate.rootLib.load().then((Library lib) {
+    ServiceObject field = lib.variables.singleWhere((v) => v.name == 'cleanBlock');
+    return field['value'].load().then((Instance block) {
+      expect(block.isClosure, isTrue);
+      expect(block.closureCtxt.isContext, isTrue);
+      expect(block.closureCtxt.length, equals(0));
+      return block.closureCtxt.load().then((Context ctxt) {
+        expect(ctxt.parentContext.isNull, isTrue);
+      });
+    });
+  }),
+
+(Isolate isolate) =>
+  isolate.rootLib.load().then((Library lib) {
+    ServiceObject field = lib.variables.singleWhere((v) => v.name == 'copyingBlock');
+    return field['value'].load().then((Instance block) {
+      expect(block.isClosure, isTrue);
+      expect(block.closureCtxt.isContext, isTrue);
+      expect(block.closureCtxt.length, equals(1));
+      return block.closureCtxt.load().then((Context ctxt) {
+        expect(ctxt.variables.single['value'].isString, isTrue);
+        expect(ctxt.variables.single['value'].valueAsString, equals('"I could be copied into the block"'));
+        expect(block.closureCtxt.parentContext.isNull, isTrue);
+      });
+    });
+  }),
+
+(Isolate isolate) =>
+  isolate.rootLib.load().then((Library lib) {
+    ServiceObject field = lib.variables.singleWhere((v) => v.name == 'fullBlock');
+    return field['value'].load().then((Instance block) {
+      expect(block.isClosure, isTrue);
+      expect(block.closureCtxt.isContext, isTrue);
+      expect(block.closureCtxt.length, equals(1));
+      return block.closureCtxt.load().then((ctxt) {
+        expect(ctxt.variables.single['value'].isInt, isTrue);
+        expect(ctxt.variables.single['value'].valueAsString, equals('43'));
+        expect(ctxt.parentContext.isNull, isTrue);
+      });
+    });
+  }),
+
+(Isolate isolate) =>
+  isolate.rootLib.load().then((Library lib) {
+    ServiceObject field = lib.variables.singleWhere((v) => v.name == 'fullBlockWithChain');
+    return field['value'].load().then((Instance block) {
+      expect(block.isClosure, isTrue);
+      expect(block.closureCtxt.isContext, isTrue);
+      expect(block.closureCtxt.length, equals(1));
+      return block.closureCtxt.load().then((Context ctxt) {
+        expect(ctxt.variables.single['value'].isInt, isTrue);
+        expect(ctxt.variables.single['value'].valueAsString, equals('4201'));
+        expect(ctxt.parentContext.isContext, isTrue);
+        expect(ctxt.parentContext.length, equals(1));
+        return ctxt.parentContext.load().then((Context outerCtxt) {
+          expect(outerCtxt.variables.single['value'].isInt, isTrue);
+          expect(outerCtxt.variables.single['value'].valueAsString, equals('421'));
+          expect(outerCtxt.parentContext.isNull, isTrue);
+        });
+      });
+    });
+  }),
+
+];
+
+main(args) => runIsolateTests(args, tests, testeeBefore: script);