Make json-maps implement Map<String, dynamic>.

tests/corelib/map_test.dart

Index: tests/corelib/map_test.dart
diff --git a/tests/corelib/map_test.dart b/tests/corelib/map_test.dart
index 0acdbfa35347c85f3fecad4399ed3921fa1083d9..9881be945b01caeba2d0f85faa0f3f98b5f1aa64 100644
--- a/tests/corelib/map_test.dart
+++ b/tests/corelib/map_test.dart
@@ -21,8 +21,6 @@ void main() {
   test(new MapView(new SplayTreeMap()));
   test(new MapBaseMap());
   test(new MapMixinMap());
-  test(newJsonMap());
-  test(newJsonMapCustomReviver());
   testLinkedHashMap();
   testMapLiteral();
   testNullValue();
@@ -53,8 +51,6 @@ void main() {
   testNumericKeys(new LinkedHashMap<num, String>.identity());
   testNumericKeys(new MapBaseMap<num, String>());
   testNumericKeys(new MapMixinMap<num, String>());
-  testNumericKeys(newJsonMap());
-  testNumericKeys(newJsonMapCustomReviver());
 
   testNaNKeys(new Map());
   testNaNKeys(new Map<num, String>());
@@ -64,8 +60,6 @@ void main() {
   testNaNKeys(new LinkedHashMap<num, String>());
   testNaNKeys(new MapBaseMap<num, String>());
   testNaNKeys(new MapMixinMap<num, String>());
-  testNaNKeys(newJsonMap());
-  testNaNKeys(newJsonMapCustomReviver());
   // Identity maps fail the NaN-keys tests because the test assumes that
   // NaN is not equal to NaN.
 
@@ -96,8 +90,6 @@ void main() {
 
   testIterationOrder(new LinkedHashMap());
   testIterationOrder(new LinkedHashMap.identity());
-  testIterationOrder(newJsonMap());
-  testIterationOrder(newJsonMapCustomReviver());
 
   testOtherKeys(new SplayTreeMap<int, int>());
   testOtherKeys(
@@ -121,8 +113,6 @@ void main() {
       isValidKey: (v) => v is int));
   testOtherKeys(new MapBaseMap<int, int>());
   testOtherKeys(new MapMixinMap<int, int>());
-  testOtherKeys(newJsonMap());
-  testOtherKeys(newJsonMapCustomReviver());
 
   testUnmodifiableMap(const {1: 37});
   testUnmodifiableMap(new UnmodifiableMapView({1: 37}));