Use input method to control visibility of virtual keyboard

views/ime/input_method.h

Index: views/ime/input_method.h
diff --git a/views/ime/input_method.h b/views/ime/input_method.h
index 918d78c031d802ad2fd634138802dcf48b2ac5e7..666bda2b29aebebf881271c3da614c758d70f44e 100644
--- a/views/ime/input_method.h
+++ b/views/ime/input_method.h
@@ -7,6 +7,7 @@
 #pragma once
 
 #include <string>
+#include <vector>
 
 #include "base/basictypes.h"
 #include "base/i18n/rtl.h"
@@ -23,6 +24,14 @@ class TextInputClient;
 class View;
 class Widget;
 
+class TextInputTypeChangedListener {
+ public:
+  virtual void TextInputTypeChanged(View* view, ui::TextInputType type) = 0;
+
+ protected:
+  virtual ~TextInputTypeChangedListener() {}
+};
+
 // An interface implemented by an object that encapsulates a native input method
 // service provided by the underlying operation system.
 // Because on most systems, the system input method service is bound to
@@ -101,6 +110,22 @@ class InputMethod {
   // ui::TEXT_INPUT_TYPE_NONE if there is no focused text input client.
   virtual ui::TextInputType GetTextInputType() const = 0;
 
+  // Adds/Removes text input type changed listener
+  void AddTextInputTypeChangedListener(TextInputTypeChangedListener* listener);
+
+  void RemoveTextInputTypeChangedListener(
+      TextInputTypeChangedListener* listener);
+
+ protected:
+  // Notifies all listeners that the text input type is changed.
+  void TextInputTypeChanged(View* view);
+
+ private:
+  // The list of registered TextInputTypeChanged listeners.
+  typedef std::vector<TextInputTypeChangedListener*>
+      TextInputTypeChangedListenerList;
+  TextInputTypeChangedListenerList text_input_type_changed_listeners_;
+
   // TODO(suzhe): Support mouse/touch event.
 };