Add more generic support for java targets bundling multiple directories

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',
 #   'type': 'none',
 #   'variables': {
 #     'package_name': 'my_package',
 #     'apk_name': 'MyPackage',
 #     'java_in_dir': 'path/to/package/root',
 #     'resource_dir': 'res',
 #   },
 #   'includes': ['path/to/this/gypi/file'],
 # }
 #
 # Note that this assumes that there's an ant buildfile <package_name>_apk.xml in
 # java_in_dir. So, if you have package_name="content_shell" and
 # java_in_dir="content/shell/android/java" you should have a directory structure
 # like:
 #
 # content/shell/android/java/content_shell_apk.xml
 # content/shell/android/java/src/chromium/base/Foo.java
 # content/shell/android/java/src/chromium/base/Bar.java
+#
+# Required variables:
+#  package_name - Used to name the intermediate output directory and in the
+#    names of some output files.
+#  apk_name - The final apk will be named <apk_name>-debug.apk (or -release)
+#  java_in_dir - The top-level java directory. The src should be in
+#    <java_in_dir>/src.
+#  resource_dir - The directory for resources.
+# Optional/automatic variables:
+#  additional_input_paths - These paths will be included in the 'inputs' list to
+#    ensure that this target is rebuilt when one of these paths changes.
+#  additional_src_dirs - Additional directories with .java files to be compiled
+#    and included in the output of this target.
+#  generated_src_dirs - Same as additional_src_dirs except used for .java files
+#    that are generated at build time. This should be set automatically by a
+#    target's dependencies. The .java files in these directories are not
+#    included in the 'inputs' list (unlike additional_src_dirs).
+#  input_jars_paths - The path to jars to be included in the classpath. This
+#    should be filled automatically by depending on the appropriate targets.
+#  native_libs_paths - The path to any native library to be included in this
+#    target.
 
 {
   'variables': {
     'input_jars_paths': [],
     'native_libs_paths': [],
+    'additional_input_paths': [],
     'additional_src_dirs': [],
-    'additional_input_paths': [],
+    'generated_src_dirs': [],
   },
   'actions': [
     {
       'action_name': 'ant_<(package_name)_apk',
       'message': 'Building <(package_name) apk.',
       'inputs': [
         '<(java_in_dir)/<(package_name)_apk.xml',
         '<(java_in_dir)/AndroidManifest.xml',
         '<(DEPTH)/build/android/ant/common.xml',
         '<(DEPTH)/build/android/ant/sdk-targets.xml',
-        '<!@(find <(java_in_dir) -name "*.java")',
+        # If there is a separate find for additonal_src_dirs, it will find the
+        # wrong .java files when additional_src_dirs is empty.
+        '>!@(find >(java_in_dir) >(additional_src_dirs) -name "*.java")',
         '<!@(find <(java_in_dir)/<(resource_dir) -name "*")',
         '>@(input_jars_paths)',
         '>@(native_libs_paths)',
         '>@(additional_input_paths)',
       ],
       'outputs': [
         '<(PRODUCT_DIR)/apks/<(apk_name)-debug.apk',
       ],
       'action': [
         'ant',
-        '-DPRODUCT_DIR=<(ant_build_out)',
         '-DAPP_ABI=<(android_app_abi)',
         '-DANDROID_GDBSERVER=<(android_gdbserver)',
         '-DANDROID_SDK=<(android_sdk)',
         '-DANDROID_SDK_ROOT=<(android_sdk_root)',
         '-DANDROID_SDK_TOOLS=<(android_sdk_tools)',
         '-DANDROID_SDK_VERSION=<(android_sdk_version)',
         '-DANDROID_TOOLCHAIN=<(android_toolchain)',
+        '-DCHROMIUM_SRC=<(ant_build_out)/../..',
+        '-DCONFIGURATION_NAME=<(CONFIGURATION_NAME)',
+        '-DPRODUCT_DIR=<(ant_build_out)',
+
+        '-DADDITIONAL_SRC_DIRS=>(additional_src_dirs)',
+        '-DINPUT_JARS_PATHS=>(input_jars_paths)',
+        '-DGENERATED_SRC_DIRS=>(generated_src_dirs)',
         '-DPACKAGE_NAME=<(package_name)',
-        '-DCONFIGURATION_NAME=<(CONFIGURATION_NAME)',
-        '-DINPUT_JARS_PATHS=>(input_jars_paths)',
-        '-DADDITIONAL_SRC_DIRS=>(additional_src_dirs)',
-        '-DCHROMIUM_SRC=<(ant_build_out)/../..',
         '-DRESOURCE_DIR=<(resource_dir)',
+
         '-buildfile',
         '<(java_in_dir)/<(package_name)_apk.xml'
       ]
     },
   ],
 }