a === b -> identical(a, b)

samples/third_party/dromaeo/common/JSON.dart

Index: samples/third_party/dromaeo/common/JSON.dart
diff --git a/samples/third_party/dromaeo/common/JSON.dart b/samples/third_party/dromaeo/common/JSON.dart
index f3d0624abce7f7ba88d43a6b10b2ccf3a669274e..483f2a3cd1a8b8c7324d5fd8cd456b5d24f59389 100644
--- a/samples/third_party/dromaeo/common/JSON.dart
+++ b/samples/third_party/dromaeo/common/JSON.dart
@@ -344,14 +344,14 @@ class JsonParser {
     JsonToken token = _tokenizer.next();
     final result = _parseValue(token);
     token = _tokenizer.next();
-    if (token !== null) {
+    if (token != null) {
       throw 'Junk at the end';
     }
     return result;
   }
 
   _parseValue(final JsonToken token) {
-    if (token === null) {
+    if (token == null) {
       throw 'Nothing to parse';
     }
     switch (token.kind) {
@@ -414,7 +414,7 @@ class JsonParser {
 
   void _parseSequence(int endTokenKind, void parseElement(JsonToken token)) {
     JsonToken token = _tokenizer.next();
-    if (token === null) {
+    if (token == null) {
       throw 'Unexpected end of stream';
     }
     if (token.kind == endTokenKind) {
@@ -424,7 +424,7 @@ class JsonParser {
     parseElement(token);
 
     token = _tokenizer.next();
-    if (token === null) {
+    if (token == null) {
       throw 'Expected either comma or terminator';
     }
     while (token.kind != endTokenKind) {
@@ -438,7 +438,7 @@ class JsonParser {
   }
 
   void _assertTokenKind(JsonToken token, int kind) {
-    if (token === null || token.kind != kind) {
+    if (token == null || token.kind != kind) {
       throw 'Unexpected token kind: token = ${token}, expected kind = ${kind}';
     }
   }
@@ -506,7 +506,7 @@ class JsonStringifier {
   void _checkCycle(final object) {
     // TODO: use Iterables.
     for (int i = 0; i < _seen.length; i++) {
-      if (_seen[i] === object) {
+      if (identical(_seen[i], object)) {
         throw 'Cyclic structure';
       }
     }
@@ -518,13 +518,13 @@ class JsonStringifier {
       // TODO: use writeOn.
       _sb.add(_numberToString(object));
       return;
-    } else if (object === true) {
+    } else if (identical(object, true)) {
         _sb.add('true');
         return;
-    } else if (object === false) {
+    } else if (identical(object, false)) {
         _sb.add('false');
         return;
-    } else if (object === null) {
+    } else if (object == null) {
         _sb.add('null');
         return;
     } else if (object is String) {