[android_webview] Split out an apk folder from the glue folder.

android_webview/apk/system_webview_apk_common.gypi

 # 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.
+#
+# When making changes remember that this is shared with the internal .apk
+# build rules.
 {
   'type': 'none',
   'dependencies': [
     '<(DEPTH)/android_webview/android_webview.gyp:libwebviewchromium',
     '<(DEPTH)/android_webview/android_webview.gyp:android_webview_java',
     '<(DEPTH)/android_webview/android_webview.gyp:android_webview_pak',
   ],
   'variables': {
-    'android_sdk_jar': '<(DEPTH)/third_party/android_platform/webview/frameworks_1622219.jar',
-    'java_in_dir': 'java',
     'native_lib_target': 'libwebviewchromium',
     'never_lint': 1,
-    'resource_dir': 'java/res',
     'R_package': 'com.android.webview.chromium',
     'R_package_relpath': 'com/android/webview/chromium',
     'extensions_to_not_compress': 'pak',
     'asset_location': '<(PRODUCT_DIR)/android_webview_assets',
     'proguard_enabled': 'true',
-    'proguard_flags_paths': ['java/proguard.flags'],
+    'proguard_flags_paths': ['<(DEPTH)/android_webview/apk/java/proguard.flags'],
     # TODO: crbug.com/405035 Find a better solution for WebView .pak files.
     'additional_input_paths': [
       '<(PRODUCT_DIR)/android_webview_assets/webviewchromium.pak',
       '<(PRODUCT_DIR)/android_webview_assets/en-US.pak',
     ],
     'conditions': [
       ['icu_use_data_file_flag==1', {
         'additional_input_paths': [
           '<(PRODUCT_DIR)/icudtl.dat',
         ],
       }],
       ['v8_use_external_startup_data==1', {
         'additional_input_paths': [
           '<(PRODUCT_DIR)/natives_blob.bin',
           '<(PRODUCT_DIR)/snapshot_blob.bin',
         ],
       }],
     ],
   },
   'includes': [ '../../build/java_apk.gypi' ],
 }