Go bindings: Don't import 'fmt' unless it is needed.

mojo/public/tools/bindings/generators/mojom_go_generator.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 '''Generates Go source files from a mojom.Module.'''
 
 from itertools import chain
 import os
 import re
 
@@ skipping 352 matching lines @@
     # Imported kinds can only be referred to in structs, constants, enums,
     # unions and interfaces.
     all_structs = list(self.module.structs)
     for i in self.module.interfaces:
       for method in i.methods:
         all_structs.append(self._GetStructFromMethod(method))
         if method.response_parameters:
           all_structs.append(self._GetResponseStructFromMethod(method))
 
     if (len(all_structs) > 0 or len(self.module.interfaces) > 0
-        or len(self.module.unions) > 0 or len(self.module.enums) > 0):
+        or len(self.module.unions) > 0):
       imports['fmt'] = 'fmt'
       imports['mojo/public/go/bindings'] = 'bindings'
     if len(self.module.interfaces) > 0:
       imports['mojo/public/go/system'] = 'system'
     if len(all_structs) > 0:
       imports['sort'] = 'sort'
 
     for union in self.module.unions:
       for field in union.fields:
         AddImport(imports, mojom_imports, self.module, field.kind)
@@ skipping 12 matching lines @@
 
     # Mojom Type generation requires additional imports.
     defInterface = len(self.module.interfaces) > 0
     defOtherType = len(self.module.unions) + len(all_structs) + \
       len(GetAllEnums(self.module)) > 0
 
     if self.should_gen_mojom_types:
       imports['bytes'] = 'bytes'
       imports['compress/gzip'] = 'gzip'
       imports['encoding/base64'] = 'base64'
+      imports['fmt'] = 'fmt'
       imports['io/ioutil'] = 'ioutil'
+      imports['mojo/public/go/bindings'] = 'bindings'
 
     if GetPackageName(self.module) != _mojom_types_pkg_short:
       if defInterface:
         # Each Interface has a service description that uses this.
         imports[_mojom_types_pkg] = _mojom_types_pkg_short
       if defOtherType and self.should_gen_mojom_types:
         # This import is needed only if generating mojom type definitions.
         imports[_mojom_types_pkg] = _mojom_types_pkg_short
 
     if GetPackageName(self.module) != _service_describer_pkg_short and \
@@ skipping 27 matching lines @@
   # modify the |name| property. Instead we add a |go_name| property.
   def _GetResponseStructFromMethod(self, method):
     self._AddStructComputedData(False, method.response_param_struct)
     if not hasattr(method.response_param_struct, "go_name"):
       # Only generate the go_names if they have not already been generated.
       method.response_param_struct.go_name = "%s_%s_ResponseParams" % (
           GetNameForElement(method.interface), GetNameForElement(method))
       for field in method.response_param_struct.fields:
         field.go_name = "out%s" % GetNameForElement(field)
     return method.response_param_struct