Use input method to control visibility of virtual keyboard

views/ime/text_input_type_tracker.h

Index: views/ime/text_input_type_tracker.h
diff --git a/views/ime/text_input_type_tracker.h b/views/ime/text_input_type_tracker.h
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index 0000000000000000000000000000000000000000..ecd16fdbfb0765f8569376db03409a7b8f8f9273
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+++ b/views/ime/text_input_type_tracker.h
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+// Copyright (c) 2011 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.
+
+#ifndef VIEWS_IME_TEXT_INPUT_TYPE_TRACKER_H_
+#define VIEWS_IME_TEXT_INPUT_TYPE_TRACKER_H_
+#pragma once
+
+#include "base/memory/singleton.h"
+#include "base/observer_list.h"
+#include "ui/base/ime/text_input_type.h"
+
+namespace views {
+
+class Widget;
+
+// This interface should be implemented by classes that want to be notified when
+// the text input type of the focused widget is changed or the focused widget is
+// changed.
+class TextInputTypeObserver {
+ public:
+  // This function will be called, when the text input type of focused |widget|
+  // is changed or the the widget is getting/losing focus.
+  virtual void TextInputTypeChanged(ui::TextInputType type, Widget* widget) = 0;
+
+ protected:
+  virtual ~TextInputTypeObserver() {}
+};
+
+// This class is for tracking the text input type of focused widget.
+class TextInputTypeTracker {
+ public:
+  // Returns the singleton instance.
+  static TextInputTypeTracker* GetInstance();
+
+  // Adds/removes a TextInputTypeObserver |observer| to the set of
+  // active observers.
+  void AddTextInputTypeObserver(TextInputTypeObserver* observer);
+  void RemoveTextInputTypeObserver(TextInputTypeObserver* observer);
+
+  // views::InputMethod should call this function with new text input |type| and
+  // the |widget| associated with the input method, when the text input type
+  // is changed.
+  // Note: The widget should have focus or is losing focus.
+  void OnTextInputTypeChanged(ui::TextInputType type, Widget* widget);
+
+ private:
+  TextInputTypeTracker();
+  ~TextInputTypeTracker();
+
+  ObserverList<TextInputTypeObserver> text_input_type_observers_;
+
+  friend struct DefaultSingletonTraits<TextInputTypeTracker>;
+  DISALLOW_COPY_AND_ASSIGN(TextInputTypeTracker);
+};
+
+}  // namespace views
+
+#endif  // VIEWS_IME_TEXT_INPUT_TYPE_TRACKER_H_