[Android] Add gyp support for multidex.

build/android/apkbuilder_action.gypi

 # 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.
 
 # This file is a helper to java_apk.gypi. It should be used to create an
 # action that runs ApkBuilder via ANT.
 #
 # Required variables:
 #  apk_name - File name (minus path & extension) of the output apk.
 #  apk_path - Path to output apk.
@@ skipping 38 matching lines @@
   'outputs': [
     '<(apk_path)',
   ],
   'conditions': [
     ['has_code == 1', {
       'inputs': ['<(dex_path)'],
       'action': [
         '-DDEX_FILE_PATH=<(dex_path)',
       ]
     }],
+    ['enable_multidex == 1', {
+      'action': [
+        '-DMULTIDEX_ENABLED=1',
+      ]
+    }]
   ],
   'action': [
     'python', '<(DEPTH)/build/android/gyp/ant.py',
     '--',
     '-quiet',
     '-DHAS_CODE=<(has_code_str)',
     '-DANDROID_SDK_ROOT=<(android_sdk_root)',
     '-DANDROID_SDK_TOOLS=<(android_sdk_tools)',
     '-DRESOURCE_PACKAGED_APK_NAME=<(resource_packaged_apk_name)',
     '-DNATIVE_LIBS_DIR=<(native_libs_dir)',
     '-DAPK_NAME=<(apk_name)',
     '-DCONFIGURATION_NAME=<(CONFIGURATION_NAME)',
     '-DOUT_DIR=<(intermediate_dir)',
     '-DUNSIGNED_APK_PATH=<(apk_path)',
     '-DEMMA_INSTRUMENT=<(emma_instrument)',
     '-DEMMA_DEVICE_JAR=<(emma_device_jar)',
     '-Dbasedir=.',
     '-buildfile',
     '<(DEPTH)/build/android/ant/apk-package.xml',
   ]
 }