Merge "Improve performance to remove an OPTION from a SELECT element." 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 b8568e0f8846e8e88bb2d9f3d6b339bdd37880d9..21d8caa030c0c2362134f2dda82dd5212ddd0ac7 100644
--- a/third_party/WebKit/Source/core/html/HTMLSelectElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLSelectElement.cpp
@@ -845,7 +845,7 @@ void HTMLSelectElement::recalcListItems() const
     }
 }
 
-void HTMLSelectElement::resetToDefaultSelection()
+void HTMLSelectElement::resetToDefaultSelection(ResetReason reason)
 {
     // https://html.spec.whatwg.org/multipage/forms.html#ask-for-a-reset
     if (multiple())
@@ -872,6 +872,10 @@ void HTMLSelectElement::resetToDefaultSelection()
         if (!firstEnabledOption && !option->isDisabledFormControl()) {
             firstEnabledOption = option;
             firstEnabledOptionIndex = optionIndex;
+            if (reason == ResetReasonSelectedOptionRemoved) {
+                // There must be no selected OPTIONs.
+                break;
+            }
         }
         ++optionIndex;
     }
@@ -989,7 +993,9 @@ void HTMLSelectElement::optionInserted(HTMLOptionElement& option, bool optionIsS
 void HTMLSelectElement::optionRemoved(const HTMLOptionElement& option)
 {
     setRecalcListItems();
-    if (option.selected() || !m_lastOnChangeOption)
+    if (option.selected())
+        resetToDefaultSelection(ResetReasonSelectedOptionRemoved);
+    else if (!m_lastOnChangeOption)
         resetToDefaultSelection();
     if (m_lastOnChangeOption == &option)
         m_lastOnChangeOption.clear();