Aura overlay scrollbars shouldn't invalidate thumb on scroll or enabled state.

third_party/WebKit/Source/platform/scroll/ScrollbarTestSuite.h

Index: third_party/WebKit/Source/platform/scroll/ScrollbarTestSuite.h
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollbarTestSuite.h b/third_party/WebKit/Source/platform/scroll/ScrollbarTestSuite.h
index a4789a58fc390fd3036d9b87bfcd061776fab193..d04bdf2e27858fec8316e342caef0ced2562915c 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollbarTestSuite.h
+++ b/third_party/WebKit/Source/platform/scroll/ScrollbarTestSuite.h
@@ -21,6 +21,11 @@ class MockScrollableArea : public GarbageCollectedFinalized<MockScrollableArea>,
   USING_GARBAGE_COLLECTED_MIXIN(MockScrollableArea);
 
  public:
+  // Public to allow using NiceMock.
+  explicit MockScrollableArea() : m_maximumScrollOffset(ScrollOffset(0, 100)) {}
+  explicit MockScrollableArea(const ScrollOffset& offset)
+      : m_maximumScrollOffset(offset) {}
+
   static MockScrollableArea* create() { return new MockScrollableArea(); }
 
   static MockScrollableArea* create(const ScrollOffset& maximumScrollOffset) {
@@ -34,14 +39,14 @@ class MockScrollableArea : public GarbageCollectedFinalized<MockScrollableArea>,
   MOCK_CONST_METHOD1(scrollSize, int(ScrollbarOrientation));
   MOCK_CONST_METHOD0(isScrollCornerVisible, bool());
   MOCK_CONST_METHOD0(scrollCornerRect, IntRect());
-  MOCK_CONST_METHOD0(horizontalScrollbar, Scrollbar*());
-  MOCK_CONST_METHOD0(verticalScrollbar, Scrollbar*());
   MOCK_CONST_METHOD0(enclosingScrollableArea, ScrollableArea*());
   MOCK_CONST_METHOD1(visibleContentRect, IntRect(IncludeScrollbarsInRect));
   MOCK_CONST_METHOD0(contentsSize, IntSize());
   MOCK_CONST_METHOD0(scrollableAreaBoundingBox, IntRect());
   MOCK_CONST_METHOD0(layerForHorizontalScrollbar, GraphicsLayer*());
   MOCK_CONST_METHOD0(layerForVerticalScrollbar, GraphicsLayer*());
+  MOCK_CONST_METHOD0(horizontalScrollbar, Scrollbar*());
+  MOCK_CONST_METHOD0(verticalScrollbar, Scrollbar*());
 
   bool userInputScrollable(ScrollbarOrientation) const override { return true; }
   bool scrollbarsCanBeActive() const override { return true; }
@@ -73,8 +78,6 @@ class MockScrollableArea : public GarbageCollectedFinalized<MockScrollableArea>,
     m_maximumScrollOffset = maximumScrollOffset;
   }
 
-  explicit MockScrollableArea() : m_maximumScrollOffset(ScrollOffset(0, 100)) {}
-
   ScrollOffset m_scrollOffset;
   ScrollOffset m_maximumScrollOffset;
 };