[CSS Shapes] Simplify Polygon implementation

Source/core/rendering/shapes/ShapeInterval.h

Index: Source/core/rendering/shapes/ShapeInterval.h
diff --git a/Source/core/rendering/shapes/ShapeInterval.h b/Source/core/rendering/shapes/ShapeInterval.h
index 3c2fb368a72a1c4efcfdc50210ab0a2d94fa687c..c032daf0af21b141f5e456516b42eb4664d0793e 100644
--- a/Source/core/rendering/shapes/ShapeInterval.h
+++ b/Source/core/rendering/shapes/ShapeInterval.h
@@ -48,7 +48,7 @@ public:
     T x1() const { return m_x1; }
     T x2() const { return m_x2; }
     T width() const { return m_x2 - m_x1; }
-    bool isEmpty() const { return m_x1 == m_x2; }
+    bool isEmpty() const { return !m_x1 && !m_x2; }
 
     void setX1(T x1)
     {
@@ -79,131 +79,6 @@ public:
         return x1() <= interval.x1() && x2() >= interval.x2();
     }
 
-    ShapeInterval<T> intersect(const ShapeInterval<T>& interval) const
-    {
-        ASSERT(overlaps(interval));
-        return ShapeInterval<T>(std::max<T>(x1(), interval.x1()), std::min<T>(x2(), interval.x2()));
-    }
-
-    typedef Vector<ShapeInterval<T> > ShapeIntervals;
-    typedef typename ShapeIntervals::const_iterator const_iterator;
-    typedef typename ShapeIntervals::iterator iterator;
-
-    static void uniteShapeIntervals(const ShapeIntervals& a, const ShapeIntervals& b, ShapeIntervals& result)
-    {
-        ASSERT(shapeIntervalsAreSortedAndDisjoint(a) && shapeIntervalsAreSortedAndDisjoint(b));
-
-        if (a.isEmpty() || a == b) {
-            result.appendRange(b.begin(), b.end());
-            return;
-        }
-
-        if (b.isEmpty()) {
-            result.appendRange(a.begin(), a.end());
-            return;
-        }
-
-        const_iterator aNext = a.begin();
-        const_iterator bNext = b.begin();
-
-        while (aNext != a.end() || bNext != b.end()) {
-            const_iterator next = (bNext == b.end() || (aNext != a.end() && aNext->x1() < bNext->x1())) ? aNext++ : bNext++;
-            if (result.isEmpty() || !result.last().overlaps(*next))
-                result.append(*next);
-            else
-                result.last().setX2(std::max<T>(result.last().x2(), next->x2()));
-        }
-    }
-
-    static void intersectShapeIntervals(const ShapeIntervals& a, const ShapeIntervals& b, ShapeIntervals& result)
-    {
-        ASSERT(shapeIntervalsAreSortedAndDisjoint(a) && shapeIntervalsAreSortedAndDisjoint(b));
-
-        if (a.isEmpty() || b.isEmpty())
-            return;
-
-        if (a == b) {
-            result.appendRange(a.begin(), a.end());
-            return;
-        }
-
-        const_iterator aNext = a.begin();
-        const_iterator bNext = b.begin();
-        const_iterator working = aNext->x1() < bNext->x1() ? aNext++ : bNext++;
-
-        while (aNext != a.end() || bNext != b.end()) {
-            const_iterator next = (bNext == b.end() || (aNext != a.end() && aNext->x1() < bNext->x1())) ? aNext++ : bNext++;
-            if (working->overlaps(*next)) {
-                result.append(working->intersect(*next));
-                if (next->x2() > working->x2())
-                    working = next;
-            } else {
-                working = next;
-            }
-        }
-    }
-
-    static void subtractShapeIntervals(const ShapeIntervals& a, const ShapeIntervals& b, ShapeIntervals& result)
-    {
-        ASSERT(shapeIntervalsAreSortedAndDisjoint(a) && shapeIntervalsAreSortedAndDisjoint(b));
-
-        if (a.isEmpty() || a == b)
-            return;
-
-        if (b.isEmpty()) {
-            result.appendRange(a.begin(), a.end());
-            return;
-        }
-
-        const_iterator aNext = a.begin();
-        const_iterator bNext = b.begin();
-        ShapeInterval<T> aValue = *aNext;
-        ShapeInterval<T> bValue = *bNext;
-
-        do {
-            bool aIncrement = false;
-            bool bIncrement = false;
-
-            if (bValue.contains(aValue)) {
-                aIncrement = true;
-            } else if (aValue.contains(bValue)) {
-                if (bValue.x1() > aValue.x1())
-                    result.append(ShapeInterval<T>(aValue.x1(), bValue.x1()));
-                if (aValue.x2() > bValue.x2())
-                    aValue.setX1(bValue.x2());
-                else
-                    aIncrement = true;
-                bIncrement = true;
-            } else if (aValue.overlaps(bValue)) {
-                if (aValue.x1() < bValue.x1()) {
-                    result.append(ShapeInterval<T>(aValue.x1(), bValue.x1()));
-                    aIncrement = true;
-                } else {
-                    aValue.setX1(bValue.x2());
-                    bIncrement = true;
-                }
-            } else {
-                if (aValue.x1() < bValue.x1()) {
-                    result.append(aValue);
-                    aIncrement = true;
-                } else {
-                    bIncrement = true;
-                }
-            }
-
-            if (aIncrement && ++aNext != a.end())
-                aValue = *aNext;
-            if (bIncrement && ++bNext != b.end())
-                bValue = *bNext;
-
-        } while (aNext != a.end() && bNext != b.end());
-
-        if (aNext != a.end()) {
-            result.append(aValue);
-            result.appendRange(++aNext, a.end());
-        }
-    }
-
     bool operator==(const ShapeInterval<T>& other) const { return x1() == other.x1() && x2() == other.x2(); }
     bool operator!=(const ShapeInterval<T>& other) const { return !operator==(other); }
 
@@ -220,16 +95,6 @@ public:
 private:
     T m_x1;
     T m_x2;
-
-    static bool shapeIntervalsAreSortedAndDisjoint(const ShapeIntervals& intervals)
-    {
-        for (unsigned i = 1; i < intervals.size(); i++) {
-            if (intervals[i - 1].x2() > intervals[i].x1())
-                return false;
-        }
-
-        return true;
-    }
 };
 
 typedef ShapeInterval<int> IntShapeInterval;