Fix overlay scroll bar color on elements with dark background

third_party/WebKit/Source/platform/scroll/ScrollableAreaTest.cpp

 // Copyright 2015 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 "platform/scroll/ScrollableArea.h"
 
+#include "platform/graphics/Color.h"
 #include "platform/graphics/GraphicsLayer.h"
 #include "platform/scroll/ScrollbarTheme.h"
 #include "platform/scroll/ScrollbarThemeMock.h"
 #include "platform/testing/TestingPlatformSupport.h"
 #include "public/platform/Platform.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blink {
 
@@ skipping 256 matching lines @@
     EXPECT_TRUE(layerForVerticalScrollbar.hasTrackedPaintInvalidations());
     EXPECT_FALSE(horizontalScrollbar->trackNeedsRepaint());
     EXPECT_FALSE(horizontalScrollbar->thumbNeedsRepaint());
     EXPECT_FALSE(verticalScrollbar->trackNeedsRepaint());
     EXPECT_FALSE(verticalScrollbar->thumbNeedsRepaint());
 
     // Forced GC in order to finalize objects depending on the mock object.
     Heap::collectAllGarbage();
 }
 
+TEST_F(ScrollableAreaTest, RecalculatesScrollbarOverlayIfBackgroundChanges)
+{
+    OwnPtrWillBeRawPtr<MockScrollableArea> scrollableArea = MockScrollableArea::create(IntPoint(0, 100));
+
+    EXPECT_EQ(ScrollbarOverlayStyleDefault, scrollableArea->getScrollbarOverlayStyle());
+    scrollableArea->recalculateScrollbarOverlayStyle(Color(34, 85, 51));
+    EXPECT_EQ(ScrollbarOverlayStyleLight, scrollableArea->getScrollbarOverlayStyle());
+    scrollableArea->recalculateScrollbarOverlayStyle(Color(236, 143, 185));
+    EXPECT_EQ(ScrollbarOverlayStyleDefault, scrollableArea->getScrollbarOverlayStyle());
+}
+
 } // namespace blink