Fix listbox selections with only disabled options.

Source/core/html/HTMLSelectElement.cpp

Index: Source/core/html/HTMLSelectElement.cpp
diff --git a/Source/core/html/HTMLSelectElement.cpp b/Source/core/html/HTMLSelectElement.cpp
index b7a185f684f5247b4664eb7aa09914e825ba1b27..ab9ba5e5d9ff6c374b238e2af20bab7a3cea8f6f 100644
--- a/Source/core/html/HTMLSelectElement.cpp
+++ b/Source/core/html/HTMLSelectElement.cpp
@@ -614,6 +614,9 @@ void HTMLSelectElement::selectAll()
     setActiveSelectionAnchorIndex(nextSelectableListIndex(-1));
     setActiveSelectionEndIndex(previousSelectableListIndex(-1));
 
+    if (m_activeSelectionAnchorIndex < 0)

[keishi, 2014/12/02 02:40:13]

I think updateListBoxSelection should just be able to handle the no active
selection case.
We can just remove the ASSERT and changed the unsigned variables to ints.

+        return;
+
     updateListBoxSelection(false, false);
     listBoxOnChange();
     setNeedsValidityCheck();