Merge "SELECT popup: Do not update popup content for arbitrary attribute change." to M52.

third_party/WebKit/Source/core/html/HTMLSelectElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLSelectElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLSelectElement.cpp b/third_party/WebKit/Source/core/html/HTMLSelectElement.cpp
index 8254a174992b257075ca6c8496c67d03e5300c9d..6da2ad4dd50b7bf62fd848db141cf31a8c3d86fd 100644
--- a/third_party/WebKit/Source/core/html/HTMLSelectElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLSelectElement.cpp
@@ -2033,8 +2033,16 @@ HTMLSelectElement::PopupUpdater::PopupUpdater(HTMLSelectElement& select)
     : m_select(select)
 {
     m_observer = MutationObserver::create(this);
+    Vector<String> filter;
+    filter.reserveCapacity(4);
+    // Observe only attributes which affect popup content.
+    filter.append(String("disabled"));
+    filter.append(String("label"));
+    filter.append(String("selected"));
+    filter.append(String("value"));
     MutationObserverInit init;
     init.setAttributes(true);
+    init.setAttributeFilter(filter);
     init.setCharacterData(true);
     init.setChildList(true);
     init.setSubtree(true);