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

ui/base/ime/input_method.h

Index: ui/base/ime/input_method.h
diff --git a/ui/base/ime/input_method.h b/ui/base/ime/input_method.h
index 0d4046f3e3f50e5f238d86e954b0062be1890144..4deaa543dd192d2f6470e575c7a2d0c1c46bf050 100644
--- a/ui/base/ime/input_method.h
+++ b/ui/base/ime/input_method.h
@@ -83,9 +83,14 @@ class InputMethod {
   // SetCompositionText(). |client| can be NULL. A gfx::NativeWindow which
   // implementes TextInputClient interface, e.g. NWA and RWHVA, should register
   // itself by calling the method when it is focused, and unregister itself by
-  // calling the metho with NULL when it is unfocused.
+  // calling the method with NULL when it is unfocused.
   virtual void SetFocusedTextInputClient(TextInputClient* client) = 0;
 
+  // Detaches and forgets the |client| regardless of whether it has the focus or
+  // not.  This method is meant to be called when the |client| is going to be
+  // destroyed.
+  virtual void DetachTextInputClient(TextInputClient* client) = 0;
+
   // Gets the current text input client. Returns NULL when no client is set.
   virtual TextInputClient* GetTextInputClient() const = 0;