SELECT element: Fix a DCHECK failure after crrev.com/404091

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 dadfb1192adf3185a228cc5651320979c842b65c..af775b8060a700b85276ae23f9ec73be317b2395 100644
--- a/third_party/WebKit/Source/core/html/HTMLSelectElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLSelectElement.cpp
@@ -1988,6 +1988,9 @@ HTMLOptionElement* HTMLSelectElement::optionToBeShown() const
         return toHTMLOptionElement(listItems()[m_indexToSelectOnCancel]);
     if (m_suggestedOption)
         return m_suggestedOption;
+    // TODO(tkent): We should not call optionToBeShown() in multiple() case.
+    if (multiple())
+        return selectedOption();
     DCHECK_EQ(selectedOption(), m_lastOnChangeOption);
     return m_lastOnChangeOption;
 }