Fix all dartanalyzer errors in dart:sky except the Native ones.

sky/engine/bindings/scripts/compiler.py

 #!/usr/bin/python
 # Copyright (C) 2014 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 96 matching lines @@
                 idl_file_list = sorted([line.rstrip('\n')
                                         for line in input_file])
             expanded_global_entries.append((directory, idl_file_list))
         global_header_filename = os.path.join(self.output_directory, 'DartGlobal.h')
         global_cpp_filename = os.path.join(self.output_directory, 'DartGlobal.cpp')
         self.generate_global_and_write(expanded_global_entries,
                                        (global_header_filename, global_cpp_filename))
 
     def generate_dart_blink(self, global_entries):
         global_dart_blink_filename = os.path.join(self.output_directory,
-                                                  'sky_core.dart')
+                                                  'dart_sky.dart')
         expanded_global_entries = []
         for (directory, file_list_file) in global_entries:
             with open(file_list_file) as input_file:
                 idl_file_list = sorted([line.rstrip('\n')
                                         for line in input_file])
             expanded_global_entries.append((directory, idl_file_list))
         self.generate_dart_blink_and_write(expanded_global_entries,
                                            global_dart_blink_filename)
 
 
 def main():
     options, filename = parse_options()
     idl_compiler = IdlCompilerDart(options.output_directory,
                                    interfaces_info_filename=options.interfaces_info_file,
                                    only_if_changed=options.write_file_only_if_changed)
     if bool(options.global_entries):
         idl_compiler.generate_global(options.global_entries)
     elif bool(options.blink_global_entries):
         idl_compiler.generate_dart_blink(options.blink_global_entries)
     else:
         idl_compiler.compile_file(filename)
 
 
 if __name__ == '__main__':
     sys.exit(main())