[Android] Enable multidex for debug builds of ChromePublic.

chrome/android/chrome_apk.gyp

 # 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.
 {
   'includes': [
     '../../chrome/chrome_android_paks.gypi', # Included for the list of pak resources.
     '../../build/util/version.gypi'
    ],
   'variables': {
     'chromium_code': 1,
@@ skipping 182 matching lines @@
     {
       # GN: //chrome/android:chrome_public_apk
       'target_name': 'chrome_public_apk',
       'type': 'none',
       'variables': {
         'android_manifest_path': '<(chrome_public_apk_manifest)',
         'apk_name': 'ChromePublic',
         'native_lib_target': 'libchrome_public',
         'java_in_dir': 'java',
         'resource_dir': '../../chrome/android/java/res_chromium',
+        'enable_multidex': 1,
+        'enable_multidex_configurations': ['Debug'],
         'conditions': [
           # Only attempt loading the library from the APK for 64 bit devices
           # until the number of 32 bit devices which don't support this
           # approach falls to a minimal level -  http://crbug.com/390618.
           ['chrome_apk_use_chromium_linker==1 and profiling==0 and (target_arch == "arm64" or target_arch == "x86_64")', {
             'load_library_from_zip': 1,
           }],
         ],
       },
       'dependencies': [
@@ skipping 203 matching lines @@
       }
     ],
   ],
 }
 
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