Update animation when changes in animation keyframes are detected.

Source/core/css/CSSKeyframesRule.cpp

Index: Source/core/css/CSSKeyframesRule.cpp
diff --git a/Source/core/css/CSSKeyframesRule.cpp b/Source/core/css/CSSKeyframesRule.cpp
index a1e8ef314bc26eb8c987bd897c9c8bc86b592c90..56305249c53fcaa6ccba8d435eca06fd4c60ca03 100644
--- a/Source/core/css/CSSKeyframesRule.cpp
+++ b/Source/core/css/CSSKeyframesRule.cpp
@@ -37,6 +37,7 @@ namespace blink {
 
 StyleRuleKeyframes::StyleRuleKeyframes()
     : StyleRuleBase(Keyframes)
+    , m_styleChangeCounter(0)
 {
 }
 
@@ -45,6 +46,7 @@ StyleRuleKeyframes::StyleRuleKeyframes(const StyleRuleKeyframes& o)
     , m_keyframes(o.m_keyframes)
     , m_name(o.m_name)
     , m_isPrefixed(o.m_isPrefixed)
+    , m_styleChangeCounter(o.m_styleChangeCounter)
 {
 }