Remove mainthread overhang painting code

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 "config.h"
 
 #include "platform/scroll/ScrollableArea.h"
 
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
@@ skipping 11 matching lines @@
     MOCK_CONST_METHOD1(scrollSize, int(ScrollbarOrientation));
     MOCK_METHOD2(invalidateScrollbar, void(Scrollbar*, const IntRect&));
     MOCK_CONST_METHOD0(isScrollCornerVisible, bool());
     MOCK_CONST_METHOD0(scrollCornerRect, IntRect());
     MOCK_METHOD2(invalidateScrollbarRect, void(Scrollbar*, const IntRect&));
     MOCK_METHOD1(invalidateScrollCornerRect, void(const IntRect&));
     MOCK_CONST_METHOD0(enclosingScrollableArea, ScrollableArea*());
     MOCK_CONST_METHOD0(minimumScrollPosition, IntPoint());
     MOCK_CONST_METHOD1(visibleContentRect, IntRect(IncludeScrollbarsInRect));
     MOCK_CONST_METHOD0(contentsSize, IntSize());
-    MOCK_CONST_METHOD0(overhangAmount, IntSize());
     MOCK_CONST_METHOD0(scrollbarsCanBeActive, bool());
     MOCK_CONST_METHOD0(scrollableAreaBoundingBox, IntRect());
 
     virtual bool userInputScrollable(ScrollbarOrientation) const override { return true; }
     virtual bool shouldPlaceVerticalScrollbarOnLeft() const override { return false; }
     virtual void setScrollOffset(const IntPoint& offset) override { m_scrollPosition = offset.shrunkTo(m_maximumScrollPosition); }
     virtual IntPoint scrollPosition() const override { return m_scrollPosition; }
     virtual IntPoint maximumScrollPosition() const override { return m_maximumScrollPosition; }
     virtual int visibleHeight() const override { return 768; }
     virtual int visibleWidth() const override { return 1024; }
     virtual bool scrollAnimatorEnabled() const override { return false; }
     virtual int pageStep(ScrollbarOrientation) const override { return 0; }
 
 private:
     IntPoint m_scrollPosition;
     IntPoint m_maximumScrollPosition;
 };
 
 TEST(ScrollableAreaTest, ScrollAnimatorCurrentPositionShouldBeSync)
 {
     MockScrollableArea scrollableArea(IntPoint(0, 100));
     scrollableArea.notifyScrollPositionChanged(IntPoint(0, 10000));
     EXPECT_EQ(100.0, scrollableArea.scrollAnimator()->currentPosition().y());
 }
 
 } // unnamed namespace