diff --git a/build/android/ant/apk-obfuscate.xml b/build/android/ant/apk-obfuscate.xml
deleted file mode 100644
index 094c9881ec0ce1..00000000000000
--- a/build/android/ant/apk-obfuscate.xml
+++ /dev/null
@@ -1,175 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<!--
-    Copyright (C) 2005-2008 The Android Open Source Project
-
-    Licensed under the Apache License, Version 2.0 (the "License");
-    you may not use this file except in compliance with the License.
-    You may obtain a copy of the License at
-
-         http://www.apache.org/licenses/LICENSE-2.0
-
-    Unless required by applicable law or agreed to in writing, software
-    distributed under the License is distributed on an "AS IS" BASIS,
-    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-    See the License for the specific language governing permissions and
-    limitations under the License.
--->
-
-<project default="-obfuscate">
-  <property name="verbose" value="false" />
-  <property name="out.dir" location="${OUT_DIR}" />
-  <!-- Output directories -->
-  <property name="out.dir" value="bin" />
-  <property name="out.absolute.dir" location="${out.dir}" />
-  <property name="out.classes.absolute.dir" location="${out.dir}/classes" />
-
-  <!-- tools location -->
-  <property name="sdk.dir" location="${ANDROID_SDK_ROOT}"/>
-  <property name="android.tools.dir" location="${sdk.dir}/tools" />
-
-  <property name="project.target.android.jar" location="${ANDROID_SDK_JAR}" />
-  <path id="project.target.class.path">
-    <pathelement location="${project.target.android.jar}" />
-  </path>
-
-
-  <!-- jar file from where the tasks are loaded -->
-  <path id="android.antlibs">
-      <pathelement path="${sdk.dir}/tools/lib/ant-tasks.jar" />
-  </path>
-
-  <!-- Custom tasks -->
-  <taskdef resource="anttasks.properties" classpathref="android.antlibs" />
-
-  <!-- Classpath for javac -->
-  <path id="javac.custom.classpath">
-    <filelist files="${INPUT_JARS_PATHS}"/>
-  </path>
-
-  <condition property="project.is.testapp" value="true" else="false">
-    <equals arg1="${IS_TEST_APK}" arg2="1" />
-  </condition>
-
-  <property name="proguard.enabled" value="${PROGUARD_ENABLED}" />
-  <property name="proguard.config" value="${PROGUARD_FLAGS}" />
-
-  <property name="manifest.file" value="${ANDROID_MANIFEST}" />
-  <property name="manifest.abs.file" location="${manifest.file}" />
-
-  <!-- Obfuscate target
-      This is only active in release builds when proguard.config is defined
-      in default.properties.
-
-  -->
-  <!--
-    Override obfuscate target to pass javac.custom.classpath to Proguard. SDK tools do not provide
-    any way to pass custom class paths to Proguard.
-   -->
-  <target name="-obfuscate">
-    <if condition="${project.is.testapp}">
-      <then>
-        <!-- get the project manifest package -->
-        <xpath input="${manifest.abs.file}"
-                expression="/manifest/@package" output="project.app.package" />
-        <loadresource property="project.app.packagepath">
-          <propertyresource name="project.app.package"/>
-          <filterchain>
-            <replacestring from="." to="/"/>
-          </filterchain>
-        </loadresource>
-        <property name="create.test.jar.exclusions" value="${project.app.packagepath}/R.class ${project.app.packagepath}/R$*.class ${project.app.packagepath}/Manifest.class ${project.app.packagepath}/Manifest$*.class ${project.app.packagepath}/BuildConfig.class"/>
-        <jar destfile="${TEST_JAR_PATH}"
-             excludes="${create.test.jar.exclusions}"
-             duplicate="preserve"
-             >
-          <restrict>
-            <name name="**/*.class"/>
-            <archives>
-              <zips>
-                <path refid="javac.custom.classpath"/>
-              </zips>
-            </archives>
-          </restrict>
-          <fileset dir="${out.dir}/classes"/>
-        </jar>
-      </then>
-    </if>
-    <if>
-      <condition>
-        <and>
-          <istrue value="${proguard.enabled}"/>
-          <equals arg1="${CONFIGURATION_NAME}" arg2="Release"/>
-        </and>
-      </condition>
-      <then>
-        <property name="obfuscate.absolute.dir" location="${out.absolute.dir}/proguard"/>
-        <property name="preobfuscate.jar.file" value="${obfuscate.absolute.dir}/original.jar"/>
-        <property name="obfuscated.jar.file" value="${OBFUSCATED_JAR_PATH}"/>
-        <property name="obfuscated.jar.abs.file" location="${obfuscated.jar.file}"/>
-
-        <!-- Add Proguard Tasks -->
-        <property name="proguard.jar" location="${android.tools.dir}/proguard/lib/proguard.jar"/>
-        <taskdef name="proguard" classname="proguard.ant.ProGuardTask" classpath="${proguard.jar}"/>
-
-        <!-- Set the android classpath Path object into a single property. It'll be
-                 all the jar files separated by a platform path-separator.
-                 Each path must be quoted if it contains spaces.
-        -->
-        <pathconvert property="project.target.classpath.value" refid="project.target.class.path">
-          <firstmatchmapper>
-            <regexpmapper from='^([^ ]*)( .*)$$' to='"\1\2"'/>
-            <identitymapper/>
-          </firstmatchmapper>
-        </pathconvert>
-
-        <!-- Build a path object with all the jar files that must be obfuscated.
-             This include the project compiled source code and any 3rd party jar
-             files. -->
-        <path id="project.all.classes.path">
-          <pathelement location="${preobfuscate.jar.file}"/>
-          <!-- Pass javac.custom.classpath for apks. -->
-          <path refid="javac.custom.classpath"/>
-        </path>
-        <!-- Set the project jar files Path object into a single property. It'll be
-             all the jar files separated by a platform path-separator.
-             Each path must be quoted if it contains spaces.
-        -->
-        <pathconvert property="project.all.classes.value" refid="project.all.classes.path">
-          <firstmatchmapper>
-            <regexpmapper from='^([^ ]*)( .*)$$' to='"\1\2"'/>
-            <identitymapper/>
-          </firstmatchmapper>
-        </pathconvert>
-
-        <!-- Turn the path property ${proguard.config} from an A:B:C property
-             into a series of includes: -include A -include B -include C
-             suitable for processing by the ProGuard task. Note - this does
-             not include the leading '-include "' or the closing '"'; those
-             are added under the <proguard> call below.
-        -->
-        <path id="proguard.configpath">
-          <filelist files="${proguard.config}"/>
-        </path>
-        <pathconvert pathsep='" -include "' property="proguard.configcmd"
-          refid="proguard.configpath"/>
-
-        <mkdir   dir="${obfuscate.absolute.dir}"/>
-        <delete file="${preobfuscate.jar.file}"/>
-        <delete file="${obfuscated.jar.abs.file}"/>
-        <jar basedir="${out.classes.absolute.dir}"
-          destfile="${preobfuscate.jar.file}"/>
-        <proguard>
-          -include      "${proguard.configcmd}"
-          -injars       ${project.all.classes.value}
-          -outjars      "${obfuscated.jar.abs.file}"
-          -libraryjars  ${project.target.classpath.value}
-          -dump         "${obfuscate.absolute.dir}/dump.txt"
-          -printseeds   "${obfuscate.absolute.dir}/seeds.txt"
-          -printusage   "${obfuscate.absolute.dir}/usage.txt"
-          -printmapping "${obfuscate.absolute.dir}/mapping.txt"
-        </proguard>
-      </then>
-    </if>
-    <touch file="${STAMP}" />
-  </target>
-</project>
diff --git a/build/android/gyp/apk_obfuscate.py b/build/android/gyp/apk_obfuscate.py
new file mode 100755
index 00000000000000..1e2eccf1745107
--- /dev/null
+++ b/build/android/gyp/apk_obfuscate.py
@@ -0,0 +1,132 @@
+#!/usr/bin/env python
+#
+# Copyright 2014 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.
+
+"""Generates the obfuscated jar and test jar for an apk.
+
+If proguard is not enabled or 'Release' is not in the configuration name,
+obfuscation will be a no-op.
+"""
+
+import fnmatch
+import optparse
+import os
+import sys
+import zipfile
+
+from util import build_utils
+
+def ParseArgs(argv):
+  parser = optparse.OptionParser()
+  parser.add_option('--android-sdk', help='path to the Android SDK folder')
+  parser.add_option('--android-sdk-tools',
+                    help='path to the Android SDK build tools folder')
+  parser.add_option('--android-sdk-jar',
+                    help='path to Android SDK\'s android.jar')
+  parser.add_option('--proguard-jar-path',
+                    help='Path to proguard.jar in the sdk')
+
+  parser.add_option('--input-jars-paths',
+                    help='Path to jars to include in obfuscated jar')
+
+  parser.add_option('--proguard-config-files',
+                    help='Paths to proguard config files')
+
+  parser.add_option('--configuration-name',
+                    help='Gyp configuration name (i.e. Debug, Release)')
+  parser.add_option('--proguard-enabled', action='store_true',
+                    help='Set if proguard is enabled for this target.')
+
+  parser.add_option('--obfuscated-jar-path',
+                    help='Output path for obfuscated jar.')
+
+  parser.add_option('--testapp', action='store_true',
+                    help='Set this if building an instrumentation test apk')
+  parser.add_option('--test-jar-path',
+                    help='Output path for jar containing all the test apk\'s '
+                    'code.')
+
+  parser.add_option('--stamp', help='File to touch on success')
+
+  (options, args) = parser.parse_args(argv)
+
+  if args:
+    parser.error('No positional arguments should be given. ' + str(args))
+
+  # Check that required options have been provided.
+  required_options = (
+      'android_sdk',
+      'android_sdk_tools',
+      'android_sdk_jar',
+      'proguard_jar_path',
+      'input_jars_paths',
+      'configuration_name',
+      'obfuscated_jar_path',
+      )
+  build_utils.CheckOptions(options, parser, required=required_options)
+
+  return options, args
+
+
+def main(argv):
+  options, _ = ParseArgs(argv)
+
+  library_classpath = [options.android_sdk_jar]
+  javac_custom_classpath = build_utils.ParseGypList(options.input_jars_paths)
+
+  dependency_class_filters = [
+      '*R.class', '*R$*.class', '*Manifest.class', '*BuildConfig.class']
+
+  def DependencyClassFilter(name):
+    for name_filter in dependency_class_filters:
+      if fnmatch.fnmatch(name, name_filter):
+        return False
+    return True
+
+  if options.testapp:
+    with zipfile.ZipFile(options.test_jar_path, 'w') as test_jar:
+      for jar in build_utils.ParseGypList(options.input_jars_paths):
+        with zipfile.ZipFile(jar, 'r') as jar_zip:
+          for name in filter(DependencyClassFilter, jar_zip.namelist()):
+            with jar_zip.open(name) as zip_entry:
+              test_jar.writestr(name, zip_entry.read())
+
+  if options.configuration_name == 'Release' and options.proguard_enabled:
+    proguard_project_classpath = javac_custom_classpath
+
+    proguard_cmd = [
+        'java', '-jar', options.proguard_jar_path,
+        '-forceprocessing',
+        '-injars', ':'.join(proguard_project_classpath),
+        '-libraryjars', ':'.join(library_classpath),
+        '-outjars', options.obfuscated_jar_path,
+        '-dump', options.obfuscated_jar_path + '.dump',
+        '-printseeds', options.obfuscated_jar_path + '.seeds',
+        '-printusage', options.obfuscated_jar_path + '.usage',
+        '-printmapping', options.obfuscated_jar_path + '.mapping',
+        ]
+
+    for proguard_file in build_utils.ParseGypList(
+        options.proguard_config_files):
+      proguard_cmd += ['-include', proguard_file]
+
+    build_utils.CheckOutput(proguard_cmd)
+  else:
+    output_files = [
+        options.obfuscated_jar_path,
+        options.obfuscated_jar_path + '.dump',
+        options.obfuscated_jar_path + '.seeds',
+        options.obfuscated_jar_path + '.usage',
+        options.obfuscated_jar_path + '.mapping']
+    for f in output_files:
+      if os.path.exists(f):
+        os.remove(f)
+      build_utils.Touch(f)
+
+  if options.stamp:
+    build_utils.Touch(options.stamp)
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv[1:]))
diff --git a/build/apk_fake_jar.gypi b/build/apk_fake_jar.gypi
index 2787691c342335..128b84cc2fa2b3 100644
--- a/build/apk_fake_jar.gypi
+++ b/build/apk_fake_jar.gypi
@@ -12,14 +12,4 @@
       'library_dexed_jars_paths': ['>(apk_output_jar_path)'],
     },
   },
-  # Add an action with the appropriate output. This allows the generated
-  # buildfiles to determine which target the output corresponds to.
-  'actions': [
-    {
-      'action_name': 'fake_generate_jar',
-      'inputs': [],
-      'outputs': ['>(apk_output_jar_path)'],
-      'action': [],
-    },
-  ],
 }
diff --git a/build/java_apk.gypi b/build/java_apk.gypi
index b654ad88bddba7..9e2b937a39be78 100644
--- a/build/java_apk.gypi
+++ b/build/java_apk.gypi
@@ -98,6 +98,7 @@
     'jar_excluded_classes': [],
     'jar_path': '<(PRODUCT_DIR)/lib.java/<(jar_name)',
     'obfuscated_jar_path': '<(intermediate_dir)/obfuscated.jar',
+    'test_jar_path': '<(PRODUCT_DIR)/test.lib.java/<(apk_name).jar',
     'dex_path': '<(intermediate_dir)/classes.dex',
     'emma_device_jar': '<(android_sdk_root)/tools/lib/emma_device.jar',
     'android_manifest_path%': '<(java_in_dir)/AndroidManifest.xml',
@@ -585,6 +586,7 @@
       ],
       'outputs': [
         '<(jar_stamp)',
+        '<(jar_path)',
       ],
       'action': [
         'python', '<(DEPTH)/build/android/gyp/jar.py',
@@ -595,43 +597,72 @@
       ]
     },
     {
-      'action_name': 'ant_obfuscate_<(_target_name)',
+      'action_name': 'obfuscate_<(_target_name)',
       'message': 'Obfuscating <(_target_name)',
+      'variables': {
+        'additional_obfuscate_options': [],
+        'proguard_out_dir': '<(intermediate_dir)/proguard',
+        'proguard_input_jar_paths': [
+          '>@(input_jars_paths)',
+          '<(jar_path)',
+        ],
+        'conditions': [
+          ['is_test_apk == 1', {
+            'additional_obfuscate_options': [
+              '--testapp',
+            ],
+          }],
+          ['proguard_enabled == "true"', {
+            'additional_obfuscate_options': [
+              '--proguard-enabled',
+            ],
+          }],
+        ],
+      },
+      'conditions': [
+        ['is_test_apk == 1', {
+          'outputs': [
+            '<(test_jar_path)',
+          ],
+        }],
+      ],
       'inputs': [
-        '<(DEPTH)/build/android/ant/apk-obfuscate.xml',
+        '<(DEPTH)/build/android/gyp/apk_obfuscate.py',
         '<(DEPTH)/build/android/gyp/util/build_utils.py',
-        '<(DEPTH)/build/android/gyp/ant.py',
-        '<(android_manifest_path)',
         '>@(proguard_flags_paths)',
-        '<(instr_stamp)',
+        '>@(proguard_input_jar_paths)',
       ],
       'outputs': [
         # This lists obfuscate_stamp instead of obfuscated_jar_path because
         # ant only writes the latter if the md5 of the inputs changes.
         '<(obfuscate_stamp)',
+
+        # In non-Release builds, these paths will all be empty files.
+        '<(obfuscated_jar_path)',
+        '<(obfuscated_jar_path).dump',
+        '<(obfuscated_jar_path).seeds',
+        '<(obfuscated_jar_path).mapping',
+        '<(obfuscated_jar_path).usage',
       ],
       'action': [
-        'python', '<(DEPTH)/build/android/gyp/ant.py',
-        '-quiet',
-        '-DANDROID_MANIFEST=<(android_manifest_path)',
-        '-DANDROID_SDK_JAR=<(android_sdk_jar)',
-        '-DANDROID_SDK_ROOT=<(android_sdk_root)',
-        '-DANDROID_SDK_VERSION=<(android_sdk_version)',
-        '-DANDROID_SDK_TOOLS=<(android_sdk_tools)',
-        '-DAPK_NAME=<(apk_name)',
-        '-DCONFIGURATION_NAME=<(CONFIGURATION_NAME)',
-        '-DINPUT_JARS_PATHS=>(input_jars_paths)',
-        '-DIS_TEST_APK=<(is_test_apk)',
-        '-DOBFUSCATED_JAR_PATH=<(obfuscated_jar_path)',
-        '-DOUT_DIR=<(intermediate_dir)',
-        '-DPROGUARD_ENABLED=<(proguard_enabled)',
-        '-DPROGUARD_FLAGS=<(proguard_flags_paths)',
-        '-DTEST_JAR_PATH=<(PRODUCT_DIR)/test.lib.java/<(apk_name).jar',
+        'python', '<(DEPTH)/build/android/gyp/apk_obfuscate.py',
 
-        '-DSTAMP=<(obfuscate_stamp)',
-        '-Dbasedir=.',
-        '-buildfile',
-        '<(DEPTH)/build/android/ant/apk-obfuscate.xml',
+        '--configuration-name', '<(CONFIGURATION_NAME)',
+
+        '--android-sdk', '<(android_sdk)',
+        '--android-sdk-tools', '<(android_sdk_tools)',
+        '--android-sdk-jar', '<(android_sdk_jar)',
+
+        '--input-jars-paths=>(proguard_input_jar_paths)',
+        '--test-jar-path', '<(test_jar_path)',
+        '--obfuscated-jar-path', '<(obfuscated_jar_path)',
+
+        '--proguard-jar-path', '<(android_sdk_root)/tools/proguard/lib/proguard.jar',
+
+        '--proguard-config-files=<(proguard_flags_paths)',
+        '--stamp', '<(obfuscate_stamp)',
+
+        '<@(additional_obfuscate_options)',
       ],
     },
     {