Lazily initialize the v8::Isolate used by ProxyResolverV8 (in the browser process).

net/proxy/proxy_resolver_perftest.cc

 // Copyright (c) 2012 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.
 
 #include "base/base_paths.h"
 #include "base/compiler_specific.h"
 #include "base/files/file_util.h"
 #include "base/path_service.h"
 #include "base/strings/string_util.h"
 #include "base/test/perf_time_logger.h"
@@ skipping 197 matching lines @@
     CHECK(false);
     return false;
   }
 
   void OnError(int line_number, const base::string16& message) override {
     CHECK(false);
   }
 };
 
 TEST(ProxyResolverPerfTest, ProxyResolverV8) {
-  net::ProxyResolverV8::EnsureIsolateCreated();
-
   MockJSBindings js_bindings;
   net::ProxyResolverV8 resolver;
   resolver.set_js_bindings(&js_bindings);
   PacPerfSuiteRunner runner(&resolver, "ProxyResolverV8");
   runner.RunAllTests();
 }