Enable Android APKs to be build with R.java in a custom package.

build/java_apk.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 Android APKs in a consistent manner.
 #
 # To use this, create a gyp target with the following form:
 # {
 #   'target_name': 'my_package_apk',
@@ skipping 39 matching lines @@
 #  input_jars_paths - The path to jars to be included in the classpath. This
 #    should be filled automatically by depending on the appropriate targets.
 #  is_test_apk - Set to 1 if building a test apk.  This prevents resources from
 #    dependencies from being re-included.
 #  native_libs_paths - The path to any native library to be included in this
 #    target. This should be a path in <(SHARED_LIB_DIR). A stripped copy of
 #    the library will be included in the apk and symbolic links to the
 #    unstripped copy will be added to <(android_product_out) to enable native
 #    debugging.
 #  resource_dir - The directory for resources.
+#  R_package - A custom Java package to generate the resource file R.java in.
+#    By default, the package given in AndroidManifest.xml will be used.
 
 {
   'variables': {
     'asset_location%': '',
     'additional_input_paths': [],
     'input_jars_paths': [],
     'additional_src_dirs': [],
     'generated_src_dirs': [],
     'app_manifest_version_name%': '<(android_app_version_name)',
     'app_manifest_version_code%': '<(android_app_version_code)',
     'proguard_enabled%': 'false',
     'proguard_flags%': '',
     'native_libs_paths': [],
-    'manifest_package_name%': 'unknown.package.name',
+    'jar_name%': 'chromium_apk_<(package_name).jar',
     'resource_dir%':'',
-    'jar_name%': 'chromium_apk_<(package_name).jar',
+    'R_package%':'',
     'additional_res_dirs': [],
     'additional_res_packages': [],
     'is_test_apk%': 0,
   },
   'sources': [
       '<@(native_libs_paths)'
   ],
   # Pass the jar path to the apk's "fake" jar target.  This would be better as
   # direct_dependent_settings, but a variable set by a direct_dependent_settings
   # cannot be lifted in a dependent to all_dependent_settings.
@@ skipping 84 matching lines @@
         '-Dbasedir=<(java_in_dir)',
         '-buildfile',
         '<(DEPTH)/build/android/ant/chromium-apk.xml',
 
         # Specify CONFIGURATION_NAME as the target for ant to build. The
         # buildfile will then build the appropriate SDK tools target.
         '<(CONFIGURATION_NAME)',
       ]
     },
   ],
+  'conditions': [
+    ['R_package != ""', {
+      'variables': {
+        # We generate R.java in package R_package (in addition to the package
+        # listed in the AndroidManifest.xml, which is unavoidable).
+        'additional_res_dirs': ['<(DEPTH)/build/android/ant/empty/res'],
+        'additional_res_packages': ['<(R_package)'],
+      },
+    }],
+  ],
 }