TEST_F(ScrollableAreaTest, ScrollbarTrackAndThumbRepaint)
{
    ScrollbarThemeWithMockInvalidation theme;
    OwnPtrWillBeRawPtr<MockScrollableArea> scrollableArea = MockScrollableArea::create(IntPoint(0, 100));
    RefPtrWillBeRawPtr<Scrollbar> scrollbar = Scrollbar::createForTesting(scrollableArea.get(), HorizontalScrollbar, RegularScrollbar, &theme);

    EXPECT_CALL(theme, shouldRepaintAllPartsOnInvalidation()).WillRepeatedly(Return(true));
    EXPECT_TRUE(scrollbar->trackNeedsRepaint());
    EXPECT_TRUE(scrollbar->thumbNeedsRepaint());
    scrollbar->setNeedsPaintInvalidation(NoPart);
    EXPECT_TRUE(scrollbar->trackNeedsRepaint());
    EXPECT_TRUE(scrollbar->thumbNeedsRepaint());

    scrollbar->clearTrackNeedsRepaint();
    scrollbar->clearThumbNeedsRepaint();
    EXPECT_FALSE(scrollbar->trackNeedsRepaint());
    EXPECT_FALSE(scrollbar->thumbNeedsRepaint());
    scrollbar->setNeedsPaintInvalidation(ThumbPart);
    EXPECT_TRUE(scrollbar->trackNeedsRepaint());
    EXPECT_TRUE(scrollbar->thumbNeedsRepaint());

    // When not all parts are repainted on invalidation,
    // setNeedsPaintInvalidation sets repaint bits only on the requested parts.
    EXPECT_CALL(theme, shouldRepaintAllPartsOnInvalidation()).WillRepeatedly(Return(false));
    scrollbar->clearTrackNeedsRepaint();
    scrollbar->clearThumbNeedsRepaint();
    EXPECT_FALSE(scrollbar->trackNeedsRepaint());
    EXPECT_FALSE(scrollbar->thumbNeedsRepaint());
    scrollbar->setNeedsPaintInvalidation(ThumbPart);
    EXPECT_FALSE(scrollbar->trackNeedsRepaint());
    EXPECT_TRUE(scrollbar->thumbNeedsRepaint());

    // Forced GC in order to finalize objects depending on the mock object.
    Heap::collectAllGarbage();
}
TEST_F(ScrollableAreaTest, InvalidatesCompositedScrollbarsIfPartsNeedRepaint)
{
    ScrollbarThemeWithMockInvalidation theme;
    OwnPtrWillBeRawPtr<MockScrollableArea> scrollableArea = MockScrollableArea::create(IntPoint(100, 100));
    RefPtrWillBeRawPtr<Scrollbar> horizontalScrollbar = Scrollbar::createForTesting(scrollableArea.get(), HorizontalScrollbar, RegularScrollbar, &theme);
    horizontalScrollbar->clearTrackNeedsRepaint();
    horizontalScrollbar->clearThumbNeedsRepaint();
    RefPtrWillBeRawPtr<Scrollbar> verticalScrollbar = Scrollbar::createForTesting(scrollableArea.get(), VerticalScrollbar, RegularScrollbar, &theme);
    verticalScrollbar->clearTrackNeedsRepaint();
    verticalScrollbar->clearThumbNeedsRepaint();
    EXPECT_CALL(*scrollableArea, horizontalScrollbar()).WillRepeatedly(Return(horizontalScrollbar.get()));
    EXPECT_CALL(*scrollableArea, verticalScrollbar()).WillRepeatedly(Return(verticalScrollbar.get()));

    // Composited scrollbars only need repainting when parts become invalid
    // (e.g. if the track changes appearance when the thumb reaches the end).
    MockGraphicsLayerClient graphicsLayerClient;
    MockGraphicsLayer layerForHorizontalScrollbar(&graphicsLayerClient);
    layerForHorizontalScrollbar.setDrawsContent(true);
    layerForHorizontalScrollbar.setSize(FloatSize(10, 10));
    MockGraphicsLayer layerForVerticalScrollbar(&graphicsLayerClient);
    layerForVerticalScrollbar.setDrawsContent(true);
    layerForVerticalScrollbar.setSize(FloatSize(10, 10));
    EXPECT_CALL(*scrollableArea, layerForHorizontalScrollbar()).WillRepeatedly(Return(&layerForHorizontalScrollbar));
    EXPECT_CALL(*scrollableArea, layerForVerticalScrollbar()).WillRepeatedly(Return(&layerForVerticalScrollbar));
    ASSERT_TRUE(scrollableArea->hasLayerForHorizontalScrollbar());
    ASSERT_TRUE(scrollableArea->hasLayerForVerticalScrollbar());
    EXPECT_CALL(theme, shouldRepaintAllPartsOnInvalidation()).WillRepeatedly(Return(false));

    // First, we'll scroll horizontally, and the theme will require repainting
    // the back button (i.e. the track).
    EXPECT_CALL(theme, invalidateOnThumbPositionChange(_, _, _)).WillOnce(Return(BackButtonStartPart));
    scrollableArea->setScrollPosition(DoublePoint(50, 0), ProgrammaticScroll);
    EXPECT_TRUE(layerForHorizontalScrollbar.hasTrackedPaintInvalidations());
    EXPECT_FALSE(layerForVerticalScrollbar.hasTrackedPaintInvalidations());
    EXPECT_TRUE(horizontalScrollbar->trackNeedsRepaint());
    EXPECT_FALSE(horizontalScrollbar->thumbNeedsRepaint());
    layerForHorizontalScrollbar.resetTrackedPaintInvalidations();
    horizontalScrollbar->clearTrackNeedsRepaint();

    // Next, we'll scroll vertically, but invalidate the thumb.
    EXPECT_CALL(theme, invalidateOnThumbPositionChange(_, _, _)).WillOnce(Return(ThumbPart));
    scrollableArea->setScrollPosition(DoublePoint(50, 50), ProgrammaticScroll);
    EXPECT_FALSE(layerForHorizontalScrollbar.hasTrackedPaintInvalidations());
    EXPECT_TRUE(layerForVerticalScrollbar.hasTrackedPaintInvalidations());
    EXPECT_FALSE(verticalScrollbar->trackNeedsRepaint());
    EXPECT_TRUE(verticalScrollbar->thumbNeedsRepaint());
    layerForVerticalScrollbar.resetTrackedPaintInvalidations();
    verticalScrollbar->clearThumbNeedsRepaint();

    // Next we'll scroll in both, but the thumb position moving requires no
    // invalidations. Nonetheless the GraphicsLayer should be invalidated,
    // because we still need to update the underlying layer (though no
    // rasterization will be required).
    EXPECT_CALL(theme, invalidateOnThumbPositionChange(_, _, _)).Times(2).WillRepeatedly(Return(NoPart));
    scrollableArea->setScrollPosition(DoublePoint(70, 70), ProgrammaticScroll);
    EXPECT_TRUE(layerForHorizontalScrollbar.hasTrackedPaintInvalidations());
    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();
}