Fix crash around candidate window layout.

chromeos/dbus/ibus/ibus_lookup_table.cc

Index: chromeos/dbus/ibus/ibus_lookup_table.cc
diff --git a/chromeos/dbus/ibus/ibus_lookup_table.cc b/chromeos/dbus/ibus/ibus_lookup_table.cc
index 77aa07c8aea3ed8b6be48b5d62f6a9d3a5fea18b..38c565614a5a2c10ac42e0975f0ce42f468a7abc 100644
--- a/chromeos/dbus/ibus/ibus_lookup_table.cc
+++ b/chromeos/dbus/ibus/ibus_lookup_table.cc
@@ -118,8 +118,12 @@ bool PopIBusLookupTable(dbus::MessageReader* reader, IBusLookupTable* table) {
                << "5th argument should be int32.";
     return false;
   }
+
+  // Original IBus spec has third orientation IBUS_ORIENTATION_SYSTEM but it
+  // was not supported in Chrome OS. Thus do not cast from integer to enum.
   table->set_orientation(
-      static_cast<IBusLookupTable::Orientation>(orientation));
+      orientation == IBusLookupTable::HORIZONTAL ?
+      IBusLookupTable::HORIZONTAL : IBusLookupTable::VERTICAL);
 
   dbus::MessageReader text_array_reader(NULL);
   if (!ibus_object_reader.PopArray(&text_array_reader)) {