Tracking filter mutation via SVGElementProxy

third_party/WebKit/Source/core/css/resolver/MatchedPropertiesCache.cpp

Index: third_party/WebKit/Source/core/css/resolver/MatchedPropertiesCache.cpp
diff --git a/third_party/WebKit/Source/core/css/resolver/MatchedPropertiesCache.cpp b/third_party/WebKit/Source/core/css/resolver/MatchedPropertiesCache.cpp
index 24855a46543b4436be6492518461c1d8307b67a9..fbcccada76e01488b5cfd930a2eb0fa4ce7709d3 100644
--- a/third_party/WebKit/Source/core/css/resolver/MatchedPropertiesCache.cpp
+++ b/third_party/WebKit/Source/core/css/resolver/MatchedPropertiesCache.cpp
@@ -136,6 +136,8 @@ bool MatchedPropertiesCache::isCacheable(const StyleResolverState& state) {
     return false;
   if (style.hasVariableReferenceFromNonInheritedProperty())
     return false;
+  if (style.hasFilter() && style.filter().hasReferenceFilter())

[esprehn, 2016/10/25 01:18:42]

Hmm, can you explain why you need to turn off matched properties caching here? I
wonder why we need a strong reference inside the style value. It seems like the
style should setup observations on the Document for things with the referenced
filter id?

[fs, 2016/10/25 15:00:53]

Because mutations to the DOM tree does not reflect in the MatchResults. I guess
optionally this could be handled out-of-band of the style system by having
clients register id observers?
There's only a strong reference to the proxy (and back.) The proxy is
essentially the "observation" mechanism. I guess for the actual target element
we could use IdTargetObservers and do away with the generation mechanism.

+    return false;
   return true;
 }