Fix dynamic calls on JS interop classes.

pkg/dev_compiler/lib/js/common/dart_sdk.js

Index: pkg/dev_compiler/lib/js/common/dart_sdk.js
diff --git a/pkg/dev_compiler/lib/js/common/dart_sdk.js b/pkg/dev_compiler/lib/js/common/dart_sdk.js
index 34eb1dc43cd34117619d7c35d4255047e8205b74..654e13fcf30f6d13ddf11c49e355305c17659b8a 100644
--- a/pkg/dev_compiler/lib/js/common/dart_sdk.js
+++ b/pkg/dev_compiler/lib/js/common/dart_sdk.js
@@ -1123,6 +1123,14 @@
   dart.getType = function(obj) {
     return obj == null ? core.Object : obj.__proto__.constructor;
   };
+  dart.isJsInterop = function(obj) {
+    if (typeof obj === "function") {
+      return dart._getRuntimeType(obj) == null;
+    }
+    if (typeof obj !== "object") return false;
+    if (dart.getExtensionType(obj) != null) return false;
+    return !(obj instanceof core.Object);
+  };
   dart.getMethodType = function(type, name) {
     let sigObj = type[dart._methodSig];
     if (sigObj === void 0) return void 0;
@@ -1922,6 +1930,17 @@
       let type = dart.getType(obj);
       if (dart.test(dart.hasField(type, f)) || dart.test(dart.hasGetter(type, f))) return obj[f];
       if (dart.test(dart.hasMethod(type, f))) return dart.bind(obj, f, void 0);
+      if (dart.test(dart.isJsInterop(obj))) return obj[f];
+    }
+    return dart.noSuchMethod(obj, new dart.InvocationImpl(field, [], {isGetter: true}));
+  };
+  dart.dloadMirror = function(obj, field) {
+    let f = dart._canonicalMember(obj, field);
+    dart._trackCall(obj);
+    if (f != null) {
+      let type = dart.getType(obj);
+      if (dart.test(dart.hasField(type, f)) || dart.test(dart.hasGetter(type, f))) return obj[f];
+      if (dart.test(dart.hasMethod(type, f))) return dart.bind(obj, f, void 0);
     }
     return dart.noSuchMethod(obj, new dart.InvocationImpl(field, [], {isGetter: true}));
   };
@@ -1930,7 +1949,7 @@
     if (genericClass != null) return genericClass();
     return type;
   };
-  dart.dputLegacy = function(obj, field, value) {
+  dart.dputMirror = function(obj, field, value) {
     let f = dart._canonicalMember(obj, field);
     dart._trackCall(obj);
     if (f != null) {
@@ -1960,6 +1979,9 @@
         if (fieldType != void 0) {
           return obj[f] = dart.check(value, fieldType);
         }
+        if (dart.test(dart.isJsInterop(obj))) {
+          return obj[f] = value;
+        }
       }
     }
     return dart.noSuchMethod(obj, new dart.InvocationImpl(field, [value], {isSetter: true}));
@@ -13655,11 +13677,11 @@
     }
   });
   _js_mirrors._dload = function(obj, name) {
-    return _js_mirrors._dart.dload(obj, name);
+    return _js_mirrors._dart.dloadMirror(obj, name);
   };
   dart.lazyFn(_js_mirrors._dload, () => dynamicAndStringTodynamic());
   _js_mirrors._dput = function(obj, name, val) {
-    _js_mirrors._dart.dputLegacy(obj, name, val);
+    _js_mirrors._dart.dputMirror(obj, name, val);
   };
   dart.lazyFn(_js_mirrors._dput, () => dynamicAndStringAnddynamicTovoid());
   _js_mirrors._dcall = function(obj, args) {