Support SetFocusedTextInputClient(NULL) in InputMethodTSF

ui/base/ime/input_method_tsf.cc

Index: ui/base/ime/input_method_tsf.cc
diff --git a/ui/base/ime/input_method_tsf.cc b/ui/base/ime/input_method_tsf.cc
index ab720f11da4a6600dced99fdf7eafba0f9b5c80c..65699ce8c575166faecea9dc982f3ae6c4985afe 100644
--- a/ui/base/ime/input_method_tsf.cc
+++ b/ui/base/ime/input_method_tsf.cc
@@ -89,6 +89,11 @@ void InputMethodTSF::SetFocusedTextInputClient(TextInputClient* client) {
   if (IsWindowFocused(client)) {
     ui::TSFBridge::GetInstance()->SetFocusedClient(
         GetAttachedWindowHandle(client), client);
+  } else if (!client) {
+    // SetFocusedTextInputClient(NULL) must be interpreted as
+    // "Remove the attached client".
+    ui::TSFBridge::GetInstance()->RemoveFocusedClient(
+        ui::TSFBridge::GetInstance()->GetFocusedTextInputClient());
   }
   InputMethodWin::SetFocusedTextInputClient(client);
 }