[Bindings] Create and use V8 context snapshots

url/BUILD.gn

 # 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.
 
 import("//build/buildflag_header.gni")
 import("//testing/test.gni")
 import("features.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")
@@ skipping 54 matching lines @@
     "//base",
     "//base/third_party/dynamic_annotations",
   ]
 
   if (is_win) {
     # Don't conflict with Windows' "url.dll".
     output_name = "url_lib"
   }
 
   # ICU support.
-  if (use_platform_icu_alternatives) {
+  if (use_platform_icu_alternatives && current_toolchain == default_toolchain) {

[Yuki, 2017/05/12 15:20:11]

Why do we need this change?

[peria, 2017/06/20 10:20:14]

To use ICU alternatives on Android, but it can't be used on the host machine
(Linux).

     if (is_android) {
       sources += [ "url_canon_icu_alternatives_android.cc" ]
       deps += [
         ":url_features",
         ":url_java",
         ":url_jni_headers",
         "//base",
         "//base/third_party/dynamic_annotations",
       ]
     } else if (is_ios) {
@@ skipping 79 matching lines @@
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 
   if (!is_ios) {
     deps += [
       "//mojo/edk/system",
       "//mojo/edk/test:test_support",
       "//url/mojo:test_url_mojom_gurl",
     ]
   }
 }