Fix virtual/override/final usage in Source/core/layout/.

Source/core/layout/LayoutMultiColumnFlowThread.h

Index: Source/core/layout/LayoutMultiColumnFlowThread.h
diff --git a/Source/core/layout/LayoutMultiColumnFlowThread.h b/Source/core/layout/LayoutMultiColumnFlowThread.h
index 4aa9c5debf4b66928f4b8eef532be3a0f3b121d4..25e05de7e1d187ebbbf7413c7b9933a4b60cea14 100644
--- a/Source/core/layout/LayoutMultiColumnFlowThread.h
+++ b/Source/core/layout/LayoutMultiColumnFlowThread.h
@@ -117,11 +117,11 @@ enum BalancedColumnHeightCalculation { GuessFromFlowThreadPortion, StretchBySpac
 // https://sites.google.com/a/chromium.org/dev/developers/design-documents/multi-column-layout
 class CORE_EXPORT LayoutMultiColumnFlowThread : public LayoutFlowThread {
 public:
-    virtual ~LayoutMultiColumnFlowThread();
+    ~LayoutMultiColumnFlowThread() override;
 
     static LayoutMultiColumnFlowThread* createAnonymous(Document&, const ComputedStyle& parentStyle);
 
-    virtual bool isLayoutMultiColumnFlowThread() const override final { return true; }
+    bool isLayoutMultiColumnFlowThread() const final { return true; }
 
     LayoutBlockFlow* multiColumnBlockFlow() const { return toLayoutBlockFlow(parent()); }
 
@@ -163,14 +163,14 @@ public:
     void setColumnHeightAvailable(LayoutUnit available) { m_columnHeightAvailable = available; }
     bool progressionIsInline() const { return m_progressionIsInline; }
 
-    virtual LayoutSize columnOffset(const LayoutPoint&) const override final;
+    LayoutSize columnOffset(const LayoutPoint&) const final;
 
     // Do we need to set a new width and lay out?
     virtual bool needsNewWidth() const;
 
-    virtual LayoutPoint visualPointToFlowThreadPoint(const LayoutPoint& visualPoint) const override;
+    LayoutPoint visualPointToFlowThreadPoint(const LayoutPoint& visualPoint) const override;
 
-    virtual LayoutMultiColumnSet* columnSetAtBlockOffset(LayoutUnit) const override final;
+    LayoutMultiColumnSet* columnSetAtBlockOffset(LayoutUnit) const final;
 
     void layoutColumns(bool relayoutChildren, SubtreeLayoutScope&);
 
@@ -181,13 +181,13 @@ public:
     // Remove the spanner placeholder and return true if the specified object is no longer a valid spanner.
     bool removeSpannerPlaceholderIfNoLongerValid(LayoutBox* spannerObjectInFlowThread);
 
-    virtual const char* name() const override { return "LayoutMultiColumnFlowThread"; }
+    const char* name() const override { return "LayoutMultiColumnFlowThread"; }
 
 protected:
     LayoutMultiColumnFlowThread();
     void setProgressionIsInline(bool isInline) { m_progressionIsInline = isInline; }
 
-    virtual void layout() override;
+    void layout() override;
 
 private:
     void calculateColumnCountAndWidth(LayoutUnit& width, unsigned& count) const;
@@ -196,20 +196,20 @@ private:
     void destroySpannerPlaceholder(LayoutMultiColumnSpannerPlaceholder*);
     virtual bool descendantIsValidColumnSpanner(LayoutObject* descendant) const;
 
-    virtual void addColumnSetToThread(LayoutMultiColumnSet*) override;
-    virtual void willBeRemovedFromTree() override;
-    virtual void skipColumnSpanner(LayoutBox*, LayoutUnit logicalTopInFlowThread) override;
-    virtual void flowThreadDescendantWasInserted(LayoutObject*) final;
-    virtual void flowThreadDescendantWillBeRemoved(LayoutObject*) final;
-    virtual void flowThreadDescendantStyleWillChange(LayoutObject*, StyleDifference, const ComputedStyle& newStyle) override;
-    virtual void flowThreadDescendantStyleDidChange(LayoutObject*, StyleDifference, const ComputedStyle& oldStyle) override;
-    virtual void computePreferredLogicalWidths() override;
-    virtual void computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues&) const override;
-    virtual void updateLogicalWidth() override;
-    virtual void setPageBreak(LayoutUnit offset, LayoutUnit spaceShortage) override;
-    virtual void updateMinimumPageHeight(LayoutUnit offset, LayoutUnit minHeight) override;
-    virtual bool addForcedColumnBreak(LayoutUnit, LayoutObject* breakChild, bool isBefore, LayoutUnit* offsetBreakAdjustment = nullptr) override;
-    virtual bool isPageLogicalHeightKnown() const override;
+    void addColumnSetToThread(LayoutMultiColumnSet*) override;
+    void willBeRemovedFromTree() override;
+    void skipColumnSpanner(LayoutBox*, LayoutUnit logicalTopInFlowThread) override;
+    void flowThreadDescendantWasInserted(LayoutObject*) final;
+    void flowThreadDescendantWillBeRemoved(LayoutObject*) final;
+    void flowThreadDescendantStyleWillChange(LayoutObject*, StyleDifference, const ComputedStyle& newStyle) override;
+    void flowThreadDescendantStyleDidChange(LayoutObject*, StyleDifference, const ComputedStyle& oldStyle) override;
+    void computePreferredLogicalWidths() override;
+    void computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues&) const override;
+    void updateLogicalWidth() override;
+    void setPageBreak(LayoutUnit offset, LayoutUnit spaceShortage) override;
+    void updateMinimumPageHeight(LayoutUnit offset, LayoutUnit minHeight) override;
+    bool addForcedColumnBreak(LayoutUnit, LayoutObject* breakChild, bool isBefore, LayoutUnit* offsetBreakAdjustment = nullptr) override;
+    bool isPageLogicalHeightKnown() const override;
 
     // The last set we worked on. It's not to be used as the "current set". The concept of a
     // "current set" is difficult, since layout may jump back and forth in the tree, due to wrong