Update animation when changes in animation keyframes are detected.

Source/core/css/CSSKeyframeRule.cpp

Index: Source/core/css/CSSKeyframeRule.cpp
diff --git a/Source/core/css/CSSKeyframeRule.cpp b/Source/core/css/CSSKeyframeRule.cpp
index c5eee682cee8cd572c902952aff7c11786b174f8..f6fcd16bda4a040934309eb2e0c54df24052aca7 100644
--- a/Source/core/css/CSSKeyframeRule.cpp
+++ b/Source/core/css/CSSKeyframeRule.cpp
@@ -28,6 +28,7 @@
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/css/CSSKeyframesRule.h"
+#include "core/css/CSSStyleSheet.h"
 #include "core/css/PropertySetCSSStyleDeclaration.h"
 #include "core/css/StylePropertySet.h"
 #include "core/css/parser/CSSParser.h"
@@ -152,6 +153,11 @@ void CSSKeyframeRule::setKeyText(const String& keyText, ExceptionState& exceptio
 {
     if (!m_keyframe->setKeyText(keyText))
         exceptionState.throwDOMException(SyntaxError, "The key '" + keyText + "' is invalid and cannot be parsed");
+
+    CSSStyleSheet::RuleMutationScope mutationScope(this);

[dstockwell, 2015/01/07 00:18:33]

Is this needed? If it is, appears as though it should be called before the
mutation happens on line 153.

[shend, 2015/01/08 05:05:29]

Oops, you're right.

+
+    CSSKeyframesRule* parent = toCSSKeyframesRule(parentRule());
+    parent->m_keyframesRule->styleChanged();

[shend, 2015/01/06 00:36:18]

Should we move this logic into StyleKeyframe so that CSSKeyframeRule doesn't
know anything about style counters? If so, is it okay to keep a pointer in
StyleKeyframe to the parent StyleKeyframes?

 }
 
 CSSStyleDeclaration* CSSKeyframeRule::style() const