Add extra DCHECKing to try to catch subpixel rendering on a non-opaque

chrome/browser/ui/views/bookmarks/bookmark_bar_view_test.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/bind.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/location.h"
 #include "base/macros.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 283 matching lines @@
 
     Browser::CreateParams native_params(profile_.get());
     browser_ = chrome::CreateBrowserWithTestWindowForParams(&native_params);
 
     local_state_.reset(new ScopedTestingLocalState(
         TestingBrowserProcess::GetGlobal()));
     model_->ClearStore();
 
     bb_view_.reset(new BookmarkBarView(browser_.get(), NULL));
     bb_view_->set_owned_by_client();
+    // Real bookmark bars get a BookmarkBarViewBackground. Set a non-null

[msw, 2017/02/11 00:49:37]

optional nit: s/a non-null/an opaque/?

[Evan Stade, 2017/02/11 01:42:37]

Done.

+    // background here just to avoid triggering subpixel rendering issues.
+    bb_view_->set_background(
+        views::Background::CreateSolidBackground(SK_ColorWHITE));
     bb_view_->SetPageNavigator(&navigator_);
 
     AddTestData(CreateBigMenu());
 
     // Create the Widget. Note the initial size is given by GetPreferredSize()
     // during initialization. This occurs after the WidgetDelegate provides
     // |bb_view_| as the contents view and adds it to the hierarchy.
     ViewEventTestBase::SetUp();
 
     // Verify the layout triggered by the initial size preserves the overflow
@@ skipping 2059 matching lines @@
     ASSERT_EQ(2u, navigator_.urls().size());
     EXPECT_EQ(navigator_.urls()[0],
               model_->bookmark_bar_node()->GetChild(0)->GetChild(0)->url());
     EXPECT_EQ(navigator_.urls()[1],
               model_->bookmark_bar_node()->GetChild(0)->GetChild(2)->url());
     Done();
   }
 };
 
 VIEW_TEST(BookmarkBarViewTest27, MiddleClickOnFolderOpensAllBookmarks);