Makes sure that an input method doesn't reference to a destroyed object.

ui/base/ime/fake_input_method.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/base/ime/fake_input_method.h"
 
 #include "base/logging.h"
 #include "base/strings/string16.h"
 #include "ui/base/events/event.h"
 #include "ui/base/events/event_constants.h"
@@ skipping 37 matching lines @@
 void FakeInputMethod::SetDelegate(internal::InputMethodDelegate* delegate) {
   delegate_ = delegate;
 }
 
 void FakeInputMethod::SetFocusedTextInputClient(TextInputClient* client) {
   text_input_client_ = client;
   FOR_EACH_OBSERVER(InputMethodObserver, observers_,
                     OnTextInputStateChanged(client));
 }
 
+void FakeInputMethod::DetachTextInputClient(TextInputClient* client) {
+  if (text_input_client_ == client) {
+    text_input_client_ = NULL;
+    FOR_EACH_OBSERVER(InputMethodObserver, observers_,
+                      OnTextInputStateChanged(client));
+  }
+}
+
 TextInputClient* FakeInputMethod::GetTextInputClient() const {
   return text_input_client_;
 }
 
 bool FakeInputMethod::DispatchKeyEvent(const base::NativeEvent& native_event) {
   bool handled = false;
 #if defined(OS_WIN)
   if (native_event.message == WM_CHAR) {
     if (text_input_client_) {
       text_input_client_->InsertChar(ui::KeyboardCodeFromNative(native_event),
@@ skipping 87 matching lines @@
 
 void FakeInputMethod::AddObserver(InputMethodObserver* observer) {
   observers_.AddObserver(observer);
 }
 
 void FakeInputMethod::RemoveObserver(InputMethodObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 }  // namespace ui