Generated dart code should import transitive imports.

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

 # Copyright 2014 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 dart source files from a mojom.Module."""
 
 import errno
 import os
 import re
 import shutil
@@ skipping 583 matching lines @@
       else:
         os.symlink(full_gen_path, full_link_path)
     except OSError as e:
       # Errno 17 is file already exists. If the link fails because file already
       # exists assume another instance of this script tried to create the same
       # file and continue on.
       if e.errno != 17:
         raise e
 
   def GetImports(self, args):
+    used_imports = self.GetUsedImports(self.module)
     used_names = set()
-    for each_import in self.module.transitive_imports:
+    for each_import in used_imports.values():
       simple_name = each_import["module_name"].split(".")[0]
 
       # Since each import is assigned a library in Dart, they need to have
       # unique names.
       unique_name = simple_name
       counter = 0
       while unique_name in used_names:
         counter += 1
         unique_name = simple_name + str(counter)
 
       used_names.add(unique_name)
       each_import["unique_name"] = unique_name + '_mojom'
       counter += 1
 
       each_import["rebased_path"] = GetImportUri(each_import['module'])
-    return self.module.imports
+    return sorted(used_imports.values(), key=lambda x: x['rebased_path'])
 
   def GetImportedInterfaces(self):
     interface_to_import = {}
     for each_import in self.module.imports:
       for each_interface in each_import["module"].interfaces:
         name = each_interface.name
         interface_to_import[name] = each_import["unique_name"] + "." + name
     return interface_to_import
 
   def ImportedFrom(self):
     interface_to_import = {}
     for each_import in self.module.imports:
       for each_interface in each_import["module"].interfaces:
         name = each_interface.name
         interface_to_import[name] = each_import["unique_name"] + "."
     return interface_to_import