Fix crash on extension IME reloading on Linux Desktop with chromeos=1.

chromeos/dbus/ibus/ibus_engine_service.cc

Index: chromeos/dbus/ibus/ibus_engine_service.cc
diff --git a/chromeos/dbus/ibus/ibus_engine_service.cc b/chromeos/dbus/ibus/ibus_engine_service.cc
index a5e298dad96b8957e32ca3b6827dc6b80f2117c7..e670398fbbd5cfcde8908948435c4e8bb00cf4ff 100644
--- a/chromeos/dbus/ibus/ibus_engine_service.cc
+++ b/chromeos/dbus/ibus/ibus_engine_service.cc
@@ -142,9 +142,9 @@ class IBusEngineServiceImpl : public IBusEngineService {
   }
 
   // IBusEngineService override.
-  virtual void UnsetEngine() OVERRIDE {
-    LOG_IF(ERROR, engine_handler_ == NULL) << "There is no engine.";
-    engine_handler_ = NULL;
+  virtual void UnsetEngine(IBusEngineHandlerInterface* handler) OVERRIDE {
+    if (engine_handler_ == handler)
+      engine_handler_ = NULL;
   }
 
   // IBusEngineService override.
@@ -486,8 +486,9 @@ class IBusEngineServiceDaemonlessImpl : public IBusEngineService {
   }
 
   // IBusEngineService override.
-  virtual void UnsetEngine() OVERRIDE {
-    IBusBridge::Get()->SetEngineHandler(NULL);
+  virtual void UnsetEngine(IBusEngineHandlerInterface* handler) OVERRIDE {
+    if (IBusBridge::Get()->GetEngineHandler() == handler)
+      IBusBridge::Get()->SetEngineHandler(NULL);
   }
 
   // IBusEngineService override.