[views-mus] Prevent creating a native OzonePlatform in mus tests.

ui/views/test/widget_test_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 "ui/views/test/widget_test.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 28 matching lines @@
   EXPECT_TRUE(std::equal(expected->begin(), expected->end(), actual.begin()));
 }
 
 }  // namespace
 
 using WidgetTestTest = WidgetTest;
 
 // Ensure that Widgets with various root windows are correctly reported by
 // WidgetTest::GetAllWidgets().
 TEST_F(WidgetTestTest, GetAllWidgets) {
+  // TODO: this test transitively uses GetContext(). That should go away for
+  // aura-mus client. http://crbug.com/663781.

[Elliot Glaysher, 2017/04/10 23:46:14]

This is an example of a test which was only succeeding because it went to the
default non-mus local aura host, which provided enough data for GetContext() to
succeed here. (And now that it's disabled in mus builds, fails.)

+  if (IsMus())
+    return;
+
   // Note Widget::Widgets is a std::set ordered by pointer value, so the order
   // that |expected| is updated below is not important.
   Widget::Widgets expected;
 
   EXPECT_EQ(expected, GetAllWidgets());
 
   Widget* platform = CreateTopLevelPlatformWidget();
   ExpectAdd(&expected, platform, "platform");
 
   Widget* platform_child = CreateChildPlatformWidget(platform->GetNativeView());
@@ skipping 25 matching lines @@
 #endif  // USE_AURA
 
   ExpectClose(&expected, {desktop, desktop_child}, "desktop");
   ExpectClose(&expected, {native, native_child}, "native");
   ExpectClose(&expected, {platform, platform_child}, "platform");
   ExpectClose(&expected, {frameless}, "frameless");
 }
 
 }  // namespace views
 }  // namespace test