Fix paint property under-invalidation checking about reference filters

third_party/WebKit/Source/platform/graphics/CompositorFilterOperations.cpp

Index: third_party/WebKit/Source/platform/graphics/CompositorFilterOperations.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/CompositorFilterOperations.cpp b/third_party/WebKit/Source/platform/graphics/CompositorFilterOperations.cpp
index b40dd5322cdd6ff72702157a093ff9c3ee69386c..2747b6a88d1ba02eb9a9bdefb1722ce801787138 100644
--- a/third_party/WebKit/Source/platform/graphics/CompositorFilterOperations.cpp
+++ b/third_party/WebKit/Source/platform/graphics/CompositorFilterOperations.cpp
@@ -97,4 +97,24 @@ bool CompositorFilterOperations::operator==(
   return m_filterOperations == o.m_filterOperations;
 }
 
+#if DCHECK_IS_ON()
+bool CompositorFilterOperations::equalsIgnoringReferenceFilters(
+    const CompositorFilterOperations& o) const {
+  size_t size = m_filterOperations.size();
+  if (size != o.m_filterOperations.size())
+    return false;
+  for (size_t i = 0; i < size; ++i) {
+    const auto& operation = m_filterOperations.at(i);
+    if (operation.type() == cc::FilterOperation::REFERENCE) {
+      if (o.m_filterOperations.at(i).type() != cc::FilterOperation::REFERENCE)
+        return false;
+      continue;
+    }
+    if (operation != o.m_filterOperations.at(i))
+      return false;
+  }
+  return true;
+}
+#endif
+
 }  // namespace blink