Index: unix/ibus/mozc_engine.cc
===================================================================
--- a/unix/ibus/mozc_engine.cc	(リビジョン 35)
+++ b/unix/ibus/mozc_engine.cc	(作業コピー)
@@ -499,17 +499,19 @@
   IBusProperty *prop = NULL;
 
 #ifndef OS_CHROMEOS
-  DCHECK(prop_mozc_tool_);
-  while (prop = ibus_prop_list_get(prop_mozc_tool_->sub_props, i++)) {
-    if (!g_strcmp0(property_name, prop->key)) {
-      const MozcEngineToolProperty *entry =
-          reinterpret_cast<const MozcEngineToolProperty*>(
-              g_object_get_data(G_OBJECT(prop), kGObjectDataKey));
-      DCHECK(entry->mode);
-      if (!session_->LaunchTool(entry->mode, "")) {
-        LOG(ERROR) << "cannot launch: " << entry->mode;
+  if (IsMozcToolAvailable()) {
+    DCHECK(prop_mozc_tool_);
+    while (prop = ibus_prop_list_get(prop_mozc_tool_->sub_props, i++)) {
+      if (!g_strcmp0(property_name, prop->key)) {
+        const MozcEngineToolProperty *entry =
+            reinterpret_cast<const MozcEngineToolProperty*>(
+                g_object_get_data(G_OBJECT(prop), kGObjectDataKey));
+        DCHECK(entry->mode);
+        if (!session_->LaunchTool(entry->mode, "")) {
+          LOG(ERROR) << "cannot launch: " << entry->mode;
+        }
+        return;
       }
-      return;
     }
   }
 #endif