Make aapt and aidl paths flexible.

build/java_aidl.gypi

 # Copyright (c) 2012 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.
 
 # This file is meant to be included into a target to provide a rule
 # to build Java aidl files in a consistent manner.
 #
 # To use this, create a gyp target with the following form:
 # {
 #   'target_name': 'aidl_aidl-file-name',
@@ skipping 17 matching lines @@
 #   ...
 #
 # Optional variables:
 #  aidl_import_include - This should be an absolute path to your java src folder
 #    that contains the classes that are imported by your aidl files.
 #
 # TODO(cjhopman): dependents need to rebuild when this target's inputs have changed.
 
 {
   'variables': {
+    'aidl_path%': '<(android_sdk_tools)/aidl',
     'intermediate_dir': '<(SHARED_INTERMEDIATE_DIR)/<(_target_name)/aidl',
     'aidl_import_include%': '',
     'additional_aidl_arguments': [],
     'additional_aidl_input_paths': [],
   },
   'direct_dependent_settings': {
     'variables': {
       'generated_src_dirs': ['<(intermediate_dir)/'],
     },
   },
@@ skipping 11 matching lines @@
       'extension': 'aidl',
       'inputs': [
         '<(android_sdk)/framework.aidl',
         '<(aidl_interface_file)',
         '<@(additional_aidl_input_paths)',
       ],
       'outputs': [
         '<(intermediate_dir)/<(RULE_INPUT_ROOT).java',
       ],
       'action': [
-        '<(android_sdk_tools)/aidl',
+        '<(aidl_path)',
         '-p<(android_sdk)/framework.aidl',
         '-p<(aidl_interface_file)',
         '<@(additional_aidl_arguments)',
         '<(RULE_INPUT_PATH)',
         '<(intermediate_dir)/<(RULE_INPUT_ROOT).java',
       ],
     },
   ],
 }