[android_webview] Extract common SystemWebview parameters to .gypi file.

third_party/android_webview_glue/android_webview_glue_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.
+{
+  '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.jar',
+    'app_manifest_version_code%': '999999',
+    'java_in_dir': 'src/chromium',
+    'java_in_dir_suffix': '/java',
+    'native_lib_target': 'libwebviewchromium',
+    'never_lint': 1,
+    'resource_dir': 'src/chromium/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',
+    # 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',
+        ],
+      }],
+    ],
+  },
+  'includes': [ '../../build/java_apk.gypi' ],
+}