Adding operator== for ChainedTimingFunction

Source/core/platform/animation/TimingFunction.h

Index: Source/core/platform/animation/TimingFunction.h
diff --git a/Source/core/platform/animation/TimingFunction.h b/Source/core/platform/animation/TimingFunction.h
index abbaf4ed80228d32b76db7d9d2c0db8435178c66..52b791168da3d1c866ac6a2789faf4deea7e8490 100644
--- a/Source/core/platform/animation/TimingFunction.h
+++ b/Source/core/platform/animation/TimingFunction.h
@@ -291,9 +291,21 @@ public:
 
     virtual bool operator==(const TimingFunction& other) const
     {
-        // This class is not exposed to CSS, so this method is not required.
-        ASSERT_NOT_REACHED();
-        return false;
+        if (other.type() != ChainedFunction)
+            return false;
+
+        if (this == &other)
+            return true;
+
+        const ChainedTimingFunction* ctf = static_cast<const ChainedTimingFunction*>(&other);
+        if (ctf->m_segments.size() != m_segments.size())
+            return false;
+
+        for (size_t i = 0; i < m_segments.size(); i++) {
+            if (m_segments[i] != ctf->m_segments[i])
+                return false;
+        }
+        return true;
     }
 
 private:
@@ -311,6 +323,27 @@ private:
             return scaleFromLocal(m_timingFunction->evaluate(scaleToLocal(fraction), accuracy));
         }
 
+        bool operator==(const Segment& other) const
+        {
+            if (this == &other)
+                return true;
+
+            bool minMaxEq = m_min == other.m_min && m_max == other.m_max;
+            if (!minMaxEq)
+                return false;
+
+            if (m_timingFunction == other.m_timingFunction)
+                return true;
+
+            if (!m_timingFunction || !other.m_timingFunction)
+                return false;
+
+            return (*m_timingFunction.get()) == (*other.m_timingFunction.get());
+        }
+        bool operator!=(const Segment& other) const
+        {
+            return !operator==(other);
+        }
     private:
         double scaleToLocal(double x) const { return (x - m_min) / (m_max - m_min); }
         double scaleFromLocal(double x) const { return blend(m_min, m_max, x); }