Use switch statement instead of bit masking for EPosition.

third_party/WebKit/Source/core/layout/LayoutObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 2412 matching lines @@
     }
     bool isInFlowPositioned() const {
       return m_positionedState == IsRelativelyPositioned ||
              m_positionedState == IsStickyPositioned;
     }
     bool isPositioned() const {
       return m_positionedState != IsStaticallyPositioned;
     }
 
     void setPositionedState(int positionState) {
-      // This mask maps FixedPosition and AbsolutePosition to
+      // This maps FixedPosition and AbsolutePosition to
       // IsOutOfFlowPositioned, saving one bit.
-      m_positionedState = static_cast<PositionedState>(positionState & 0x3);
+      switch (positionState) {
+        case StaticPosition:
+          m_positionedState = IsStaticallyPositioned;
+          break;
+        case RelativePosition:
+          m_positionedState = IsRelativelyPositioned;
+          break;
+        case AbsolutePosition:
+        case FixedPosition:
+          m_positionedState = IsOutOfFlowPositioned;
+          break;
+        case StickyPosition:
+          m_positionedState = IsStickyPositioned;
+          break;
+        default:
+          NOTREACHED();
+          break;
+      }
     }
     void clearPositionedState() { m_positionedState = StaticPosition; }
 
     ALWAYS_INLINE SelectionState getSelectionState() const {
       return static_cast<SelectionState>(m_selectionState);
     }
     ALWAYS_INLINE void setSelectionState(SelectionState selectionState) {
       m_selectionState = selectionState;
     }
 
@@ skipping 277 matching lines @@
 CORE_EXPORT void showLineTree(const blink::LayoutObject*);
 CORE_EXPORT void showLayoutTree(const blink::LayoutObject* object1);
 // We don't make object2 an optional parameter so that showLayoutTree
 // can be called from gdb easily.
 CORE_EXPORT void showLayoutTree(const blink::LayoutObject* object1,
                                 const blink::LayoutObject* object2);
 
 #endif
 
 #endif  // LayoutObject_h