Updates language model on iOS.

ios/chrome/browser/translate/language_model_factory_unittest.cc

+// Copyright 2017 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 "ios/chrome/browser/translate/language_model_factory.h"
+
+#include "ios/chrome/browser/browser_state/test_chrome_browser_state.h"
+#include "ios/web/public/test/test_web_thread_bundle.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using testing::IsNull;
+using testing::Not;
+
+class LanguageModelFactoryTest : public testing::Test {
+ public:
+  LanguageModelFactoryTest() {
+    TestChromeBrowserState::Builder browser_state_builder;
+    chrome_browser_state_ = browser_state_builder.Build();
+  }
+
+  ~LanguageModelFactoryTest() override { chrome_browser_state_.reset(); }
+
+  ios::ChromeBrowserState* chrome_browser_state() {
+    return chrome_browser_state_.get();
+  }
+
+ private:
+  web::TestWebThreadBundle thread_bundle_;
+  std::unique_ptr<TestChromeBrowserState> chrome_browser_state_;
+};
+
+TEST_F(LanguageModelFactoryTest, NotCreatedInIncognito) {
+  EXPECT_THAT(translate::LanguageModelFactory::GetForBrowserState(
+                  chrome_browser_state()),
+              Not(IsNull()));
+
+  ios::ChromeBrowserState* otr_browser_state =
+      chrome_browser_state()->GetOffTheRecordChromeBrowserState();
+  translate::LanguageModel* language_model =
+      translate::LanguageModelFactory::GetForBrowserState(otr_browser_state);
+  EXPECT_THAT(language_model, IsNull());
+}