Make CSS Animations responsive to changes to their keyframe offsets

third_party/WebKit/Source/core/css/CSSKeyframeRule.cpp

Index: third_party/WebKit/Source/core/css/CSSKeyframeRule.cpp
diff --git a/third_party/WebKit/Source/core/css/CSSKeyframeRule.cpp b/third_party/WebKit/Source/core/css/CSSKeyframeRule.cpp
index 68a26637804dbcbdd4a85e544c430e483d850639..c2e043788fd450439e2a29049119205f65e5e368 100644
--- a/third_party/WebKit/Source/core/css/CSSKeyframeRule.cpp
+++ b/third_party/WebKit/Source/core/css/CSSKeyframeRule.cpp
@@ -50,6 +50,8 @@ CSSKeyframeRule::~CSSKeyframeRule()
 
 void CSSKeyframeRule::setKeyText(const String& keyText, ExceptionState& exceptionState)
 {
+    CSSStyleSheet::RuleMutationScope(this);
+
     if (!m_keyframe->setKeyText(keyText))
         exceptionState.throwDOMException(SyntaxError, "The key '" + keyText + "' is invalid and cannot be parsed");