Command class hieracy refactoring, environmentOverride extraction

dart/tools/testing/dart/utils.dart

Index: dart/tools/testing/dart/utils.dart
diff --git a/dart/tools/testing/dart/utils.dart b/dart/tools/testing/dart/utils.dart
index 59c5021b171fe9c290309a2ec59ba93a8ca4d478..eacba54e39ec566a843012384eec7bf692a18ab7 100644
--- a/dart/tools/testing/dart/utils.dart
+++ b/dart/tools/testing/dart/utils.dart
@@ -236,6 +236,36 @@ class HashCodeBuilder {
   int get value => _value;
 }
 
+bool deepJsonCompare(Object a, Object b) {
+  if (a == null || a is num || a is String) {
+    return a == b;
+  } else if (a is List) {
+    if (b is List) {
+      if (a.length != b.length) return false;
+
+      for (int i = 0; i < a.length; i++) {
+        if (!deepJsonCompare(a[i], b[i])) return false;
+      }
+      return true;
+    }
+    return false;
+  } else if (a is Map) {
+    if (b is Map) {
+      if (a.length != b.length) return false;
+
+      for (var key in a.keys) {
+        if (!b.containsKey(key)) return false;
+        if (!deepJsonCompare(a[key], b[key])) return false;
+      }
+      return true;
+    }
+    return false;
+  } else {
+    throw new Exception("Can't compare two non json-like objects "
+        "(a: ${a.runtimeType}, b: ${b.runtimeType})");
+  }
+}
+
 class UniqueObject {
   static int _nextId = 1;
   final int _hashCode;