[FYI] All-in-one OnCandidateWindow{Show,Update,Hide}

ui/base/ime/input_method_tsf.cc

 // Copyright (c) 2013 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_tsf.h"
 
 #include "ui/base/ime/text_input_client.h"
 #include "ui/base/ime/win/tsf_bridge.h"
 #include "ui/base/ime/win/tsf_event_router.h"
 
 namespace ui {
 
 class InputMethodTSF::TSFEventObserver : public TSFEventRouterObserver {
  public:
-  TSFEventObserver() : is_candidate_popup_open_(false) {}
+  TSFEventObserver() : is_candidate_popup_open_(false), window_count_(0) {}
 
   // Returns true if we know for sure that a candidate window (or IME suggest,
   // etc.) is open.
   bool IsCandidatePopupOpen() const { return is_candidate_popup_open_; }
 
   // Overridden from TSFEventRouterObserver:
   virtual void OnCandidateWindowCountChanged(size_t window_count) OVERRIDE {
     is_candidate_popup_open_ = (window_count != 0);
+    if (window_count_ == 0 && window_count) {
+      TSFBridge::GetInstance()->OnCandidateWindowShown();
+    } else if (window_count_ && window_count) {
+      TSFBridge::GetInstance()->OnCandidateWindowUpdated();
+    } else if (window_count_ && window_count == 0) {
+      TSFBridge::GetInstance()->OnCandidateWindowHidden();
+    }
+    window_count_ = window_count;
   }
 
  private:
   // True if we know for sure that a candidate window is open.
   bool is_candidate_popup_open_;
+  // Number of visible windows for showing candidates and their related
+  // information.
+  int window_count_;
 
   DISALLOW_COPY_AND_ASSIGN(TSFEventObserver);
 };
 
 InputMethodTSF::InputMethodTSF(internal::InputMethodDelegate* delegate,
                                HWND toplevel_window_handle)
     : InputMethodWin(delegate, toplevel_window_handle),
       tsf_event_observer_(new TSFEventObserver()),
       tsf_event_router_(new TSFEventRouter(tsf_event_observer_.get())) {
   // In non-Aura environment, appropriate callbacks to OnFocus() and OnBlur()
@@ skipping 110 matching lines @@
   }
   InputMethodWin::OnDidChangeFocusedClient(focused_before, focused);
 }
 
 void InputMethodTSF::ConfirmCompositionText() {
   if (!IsTextInputTypeNone())
     ui::TSFBridge::GetInstance()->ConfirmComposition();
 }
 
 }  // namespace ui