Deprecate Math object in corelib in favor of dart:math library.

pkg/i18n/date_format.dart

Index: pkg/i18n/date_format.dart
diff --git a/pkg/i18n/date_format.dart b/pkg/i18n/date_format.dart
index 08a8d560b554477ba2a985130049400df78ba252..0f3f7ea113840c2384c5f7b8a85b9e4cb6414962 100644
--- a/pkg/i18n/date_format.dart
+++ b/pkg/i18n/date_format.dart
@@ -165,6 +165,8 @@
 
 #library('date_format');
 
+#import('dart:math');
+
 #import('intl.dart');
 #import('date_time_patterns.dart');
 #import('date_symbols.dart');
@@ -527,4 +529,4 @@ class DateFormat {
     }
     return result;
   }
-}
+}