Fix crash caused by uninstalling extension IME.

chrome/browser/chromeos/input_method/ibus_engine_controller.cc

Index: chrome/browser/chromeos/input_method/ibus_engine_controller.cc
diff --git a/chrome/browser/chromeos/input_method/ibus_engine_controller.cc b/chrome/browser/chromeos/input_method/ibus_engine_controller.cc
index e52e143b3aad2adb9b76fad8b327ea0508137678..5fd91e786cca7d5d8793dc08685fb34db944f6d6 100644
--- a/chrome/browser/chromeos/input_method/ibus_engine_controller.cc
+++ b/chrome/browser/chromeos/input_method/ibus_engine_controller.cc
@@ -886,8 +886,11 @@ class IBusEngineControllerImpl : public IBusEngineController {
       g_object_unref(chromeos_engine->table);
       chromeos_engine->table = NULL;
     }
-    if (ibus_bus_is_connected(chromeos_engine->connection->ibus_)) {
-      // We can't call destroy function without ibus-daemon connection,
+    if (chromeos_engine->connection &&
+        ibus_bus_is_connected(chromeos_engine->connection->ibus_)) {
+      // Connection may be NULL since extension IME can be uninstalled before
+      // |OnDestroy| is called.
+      // We can't call |destroy| function without ibus-daemon connection,
       // otherwise browser goes into deadlock state.
       // TODO(nona): investigate the reason of dead-lock.
       IBUS_OBJECT_CLASS(ibus_chromeos_engine_parent_class)