Support multiple proguard flags from java_apk.gypi. Proguard supports multiple proguard configurati…

build/android/tests/multiple_proguards/multiple_proguards.gyp

+# Copyright (c) 2013 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.
+{
+  'variables': {
+    'chromium_code': 1,
+    'package_name': 'multiple_proguard',
+  },
+  'targets': [
+    {
+      'target_name': 'multiple_proguards_test_apk',
+      'type': 'none',
+      'variables': {
+        'app_manifest_version_name%': '<(android_app_version_name)',
+        'java_in_dir': '.',
+        'proguard_enabled': 'true',
+        'proguard_flags_paths': [
+          'proguard1.flags',
+          'proguard2.flags',
+        ],
+        'R_package': 'dummy',
+        'R_package_relpath': 'dummy',
+        'apk_name': 'MultipleProguards',
+      },
+      'dependencies': [
+        # guava has references to objects using reflection which
+        # should be ignored in proguard step.
+        '../../../../third_party/guava/guava.gyp:guava_javalib',
+      ],
+      'includes': [ '../../../../build/java_apk.gypi' ],
+    },
+  ],
+}