ExternalPopupMenu should recreate its popup only if a SELECT subtree is updated

third_party/WebKit/Source/web/ExternalPopupMenu.cpp

Index: third_party/WebKit/Source/web/ExternalPopupMenu.cpp
diff --git a/third_party/WebKit/Source/web/ExternalPopupMenu.cpp b/third_party/WebKit/Source/web/ExternalPopupMenu.cpp
index 32b217e9cf6e0236efb2c97f96220a4d275b86ac..218c1cb67121e3a4f77a4cdc333eb569e9a3028d 100644
--- a/third_party/WebKit/Source/web/ExternalPopupMenu.cpp
+++ b/third_party/WebKit/Source/web/ExternalPopupMenu.cpp
@@ -95,10 +95,7 @@ bool ExternalPopupMenu::showInternal()
         FloatQuad quad(toLayoutBox(layoutObject)->localToAbsoluteQuad(FloatQuad(toLayoutBox(layoutObject)->borderBoundingBox())));
         IntRect rect(quad.enclosingBoundingBox());
         IntRect rectInViewport = m_localFrame->view()->soonToBeRemovedContentsToUnscaledViewport(rect);
-        // TODO(tkent): If the anchor rectangle is not visible, we should not
-        // show a popup.
         m_webExternalPopupMenu->show(rectInViewport);
-        m_shownDOMTreeVersion = m_ownerElement->document().domTreeVersion();
         return true;
     } else {
         // The client might refuse to create a popup (when there is already one pending to be shown for example).
@@ -144,12 +141,14 @@ void ExternalPopupMenu::hide()
 
 void ExternalPopupMenu::updateFromElement()
 {
-    if (m_needsUpdate)
-        return;
-    // TOOD(tkent): Even if DOMTreeVersion is not changed, we should update the
+    // TOOD(tkent): Even if DOM mutation didn't happen, we should update the
     // popup location/content in some cases.  e.g. Updating ComputedStyle of the
     // SELECT element affects popup position and OPTION style.
-    if (m_shownDOMTreeVersion == m_ownerElement->document().domTreeVersion())
+}
+
+void ExternalPopupMenu::updateFromElementWithMutation()
+{
+    if (m_needsUpdate)
         return;
     m_needsUpdate = true;
     m_ownerElement->document().postTask(BLINK_FROM_HERE, createSameThreadTask(&ExternalPopupMenu::update, this));