Refactorying gule/BUILD.gn to make merging easy.

build/config/android/config.gni

 # 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.
 
 # This file contains common system config stuff for the Android build.
 
 if (is_android) {
   assert(rebase_path("//", root_build_dir) == "../../",
          "Android output directory must be nested 2 levels within src/ (" +
              "e.g.: out-gn/Debug). http://crbug.com/412935")
@@ skipping 22 matching lines @@
   if (!defined(google_play_services_library)) {
     google_play_services_library =
         "//third_party/android_tools:google_play_services_default_java"
   }
 
   if (!defined(google_play_services_resources)) {
     google_play_services_resources =
         "//third_party/android_tools:google_play_services_default_resources"
   }
 
+  webview_public_framework_jar =
+      "//third_party/android_platform/webview/frameworks_6.0.jar"
   if (!defined(webview_framework_jar)) {
-    webview_framework_jar =
-        "//third_party/android_platform/webview/frameworks_6.0.jar"
+    webview_framework_jar = webview_public_framework_jar
   }
 
   declare_args() {
     android_sdk_root = default_android_sdk_root
     android_sdk_version = default_android_sdk_version
     android_sdk_build_tools_version = default_android_sdk_build_tools_version
 
     # Libc++ library directory. Override to use a custom libc++ binary.
     android_libcpp_lib_dir = ""
 
@@ skipping 202 matching lines @@
   } else if (current_cpu == "mips64el") {
     android_app_abi = "mips64"
   } else {
     assert(false, "Unknown Android ABI: " + current_cpu)
   }
 
   if (android_libcpp_lib_dir == "") {
     android_libcpp_lib_dir = "${android_libcpp_root}/libs/${android_app_abi}"
   }
 }