Use ScopedTaskEnvironment instead of MessageLoop in tests that use v8.

chrome/test/base/v8_unit_test.cc

 // Copyright (c) 2011 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 "chrome/test/base/v8_unit_test.h"
 
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
-#include "base/message_loop/message_loop.h"
 #include "base/path_service.h"
 #include "base/strings/string_piece.h"
 #include "base/strings/stringprintf.h"
 #include "chrome/common/chrome_paths.h"
 #include "third_party/WebKit/public/web/WebKit.h"
 
 namespace {
 
 // |args| are passed through the various JavaScript logging functions such as
 // console.log. Returns a string appropriate for logging with LOG(severity).
@@ skipping 174 matching lines @@
   error_function->RemovePrototype();
   console->Set(v8::String::NewFromUtf8(isolate, "error"), error_function);
   {
     v8::Local<v8::Context> context = context_.Get(isolate);
     v8::Context::Scope context_scope(context);
     context->Global()
         ->Set(context, v8::String::NewFromUtf8(isolate, "console"),
               console->NewInstance(context).ToLocalChecked())
         .ToChecked();
   }
-
-  loop_ = base::MakeUnique<base::MessageLoop>();

[gab, 2017/05/03 17:38:36]

That's peculiar. Should check with owners if there was a reason to create
MessageLoop last.

 }
 
 void V8UnitTest::SetGlobalStringVar(const std::string& var_name,
                                     const std::string& value) {
   v8::Isolate* isolate = blink::MainThreadIsolate();
   v8::Local<v8::Context> context =
       v8::Local<v8::Context>::New(isolate, context_);
   v8::Context::Scope context_scope(context);
   context->Global()->Set(
       v8::String::NewFromUtf8(isolate,
@@ skipping 106 matching lines @@
   v8::Local<v8::Array> test_result(args[1].As<v8::Array>());
   EXPECT_EQ(2U, test_result->Length());
   if (::testing::Test::HasNonfatalFailure())
     return;
   g_test_result_ok = test_result->Get(0)->BooleanValue();
   if (!g_test_result_ok) {
     v8::String::Utf8Value message(test_result->Get(1));
     LOG(ERROR) << *message;
   }
 }