[Android] Rework multidex and enable multidex for unit_tests_apk.

build/android/java_cpp_template.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 generate Java source files from templates that are processed
 # through the host C pre-processor.
 #
 # NOTE: For generating Java conterparts to enums prefer using the java_cpp_enum
 #       rule instead.
@@ skipping 16 matching lines @@
 # itself should use the 'ClassName.template' format, and will generate
 # 'gen/templates/<target-name>/<package-name>/ClassName.java. The files which
 # template dependents on and typically included by the template should be listed
 # in template_deps variables. Any change to them will force a rebuild of
 # the template, and hence of any source that depends on it.
 #
 
 {
   # Location where all generated Java sources will be placed.
   'variables': {
-    'additional_gcc_preprocess_options': [],
     'include_path%': '<(DEPTH)',
     'output_dir': '<(SHARED_INTERMEDIATE_DIR)/templates/<(_target_name)/<(package_name)',
   },
   'direct_dependent_settings': {
     'variables': {
       # Ensure that the output directory is used in the class path
       # when building targets that depend on this one.
       'generated_src_dirs': [
         '<(output_dir)/',
       ],
@@ skipping 20 matching lines @@
         '<@(template_deps)'
       ],
       'outputs': [
         '<(output_path)',
       ],
       'action': [
         'python', '<(DEPTH)/build/android/gyp/gcc_preprocess.py',
         '--include-path=<(include_path)',
         '--output=<(output_path)',
         '--template=<(RULE_INPUT_PATH)',
-        '<@(additional_gcc_preprocess_options)',
       ],
       'message': 'Generating Java from cpp template <(RULE_INPUT_PATH)',
     }
   ],
 }