build full 64bit WebView

android_webview/config.gni

+# Copyright 2016 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.
+
+import("//build/config/android/config.gni")
+
+declare_args() {
+  # Only build 64-bit binaries in 64-bit WebView APK. 32-bit apps will not be
+  # supported; for development only.
+  build_64bit_only_webview = false

[agrieve, 2016/09/19 14:29:18]

It would be better to have:
  build_64bit_only_webview = merge_64bit_webview_and_monochrome

and change the bellow if statement to an assert

[michaelbai, 2016/09/19 21:22:26]

Thanks, since we go one variable, I will do next time

+}
+
+if (merge_64bit_webview_and_monochrome) {
+  build_64bit_only_webview = true
+}