Updates the IME state when necessary when switching top-level windows.

ui/base/ime/input_method_win.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/input_method_win.h"
 
 #include <stddef.h>
 #include <stdint.h>
 #include <cwctype>
 
@@ skipping 39 matching lines @@
       enabled_(false),
       is_candidate_popup_open_(false),
       composing_window_handle_(NULL),
       weak_ptr_factory_(this) {
   SetDelegate(delegate);
   imm32_manager_.SetInputLanguage();
 }
 
 InputMethodWin::~InputMethodWin() {}
 
+void InputMethodWin::OnFocus() {
+  InputMethodBase::OnFocus();
+  RefreshInputLanguage();
+}
+
 bool InputMethodWin::OnUntranslatedIMEMessage(
     const base::NativeEvent& event,
     InputMethod::NativeEventResult* result) {
   LRESULT original_result = 0;
   BOOL handled = FALSE;
 
   switch (event.message) {
     case WM_IME_SETCONTEXT:
       original_result = OnImeSetContext(
           event.hwnd, event.message, event.wParam, event.lParam, &handled);
@@ skipping 198 matching lines @@
 }
 
 void InputMethodWin::OnInputLocaleChanged() {
   // Note: OnInputLocaleChanged() is for capturing the input language which can
   // be used to determine the appropriate TextInputType for Omnibox.
   // See crbug.com/344834.
   // Currently OnInputLocaleChanged() on Windows relies on WM_INPUTLANGCHANGED,
   // which is known to be incompatible with TSF.
   // TODO(shuchen): Use ITfLanguageProfileNotifySink instead.
   OnInputMethodChanged();
-  imm32_manager_.SetInputLanguage();
-  UpdateIMEState();
+  RefreshInputLanguage();
 }
 
 bool InputMethodWin::IsInputLocaleCJK() const {
   return imm32_manager_.IsInputLanguageCJK();
 }
 
 bool InputMethodWin::IsCandidatePopupOpen() const {
   return is_candidate_popup_open_;
 }
 
@@ skipping 359 matching lines @@
   const gfx::Rect rect =
       display::win::ScreenWin::DIPToScreenRect(toplevel_window_handle_,
                                                dip_rect);
 
   char_positon->pt.x = rect.x();
   char_positon->pt.y = rect.y();
   char_positon->cLineHeight = rect.height();
   return 1;  // returns non-zero value when succeeded.
 }
 
+void InputMethodWin::RefreshInputLanguage() {
+  TextInputType type_original = GetTextInputType();
+  imm32_manager_.SetInputLanguage();
+  if (type_original != GetTextInputType()) {
+    // Only update the IME state when necessary.
+    // It's unnecessary to report IME state, when:
+    // 1) Switching betweeen 2 top-level windows, and the switched-away window
+    //    receives OnInputLocaleChanged.
+    // 2) The text input type is not changed by |SetInputLanguage|.
+    // Please refer to crbug.com/679564.
+    UpdateIMEState();
+  }
+}
+
 bool InputMethodWin::IsWindowFocused(const TextInputClient* client) const {
   if (!client)
     return false;
   // When Aura is enabled, |attached_window_handle| should always be a top-level
   // window. So we can safely assume that |attached_window_handle| is ready for
   // receiving keyboard input as long as it is an active window. This works well
   // even when the |attached_window_handle| becomes active but has not received
   // WM_FOCUS yet.
   return toplevel_window_handle_ &&
       GetActiveWindow() == toplevel_window_handle_;
@@ skipping 64 matching lines @@
   ui::IMEEngineHandlerInterface* engine = GetEngine();
   if (engine) {
     if (old_text_input_type != ui::TEXT_INPUT_TYPE_NONE)
       engine->FocusOut();
     if (GetTextInputType() != ui::TEXT_INPUT_TYPE_NONE)
       engine->FocusIn(context);
   }
 }
 
 }  // namespace ui