Implement sync of keyboard layout between Ozone and Wayland clients

ui/base/ime/chromeos/ime_keyboard.h

 // Copyright 2014 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 UI_BASE_IME_CHROMEOS_IME_KEYBOARD_H_
 #define UI_BASE_IME_CHROMEOS_IME_KEYBOARD_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 21 matching lines @@
   // in user preferences.
   kNumModifierKeys,
 };
 
 class UI_BASE_IME_EXPORT ImeKeyboard {
  public:
   class Observer {
    public:
     // Called when the caps lock state has changed.
     virtual void OnCapsLockChanged(bool enabled) = 0;
+
+    // Called when the layout state has changed.
+    virtual void OnLayoutChanged(const std::string& layout_name) = 0;

[reveman, 2017/06/09 21:15:18]

OnLayoutChanging as GetCurrentKeyboardLayoutName() still returns the old layout.
Alternatively keep the current name and make sure GetCurrentKeyboardLayoutName()
returns the new layout when this is called.

[jclinton, 2017/06/09 22:17:59]

Done.

   };
 
   ImeKeyboard();
   virtual ~ImeKeyboard();
   // Adds/removes observer.
   virtual void AddObserver(Observer* observer);
   virtual void RemoveObserver(Observer* observer);
 
   // Sets the current keyboard layout to |layout_name|. This function does not
   // change the current mapping of the modifier keys. Returns true on success.
-  virtual bool SetCurrentKeyboardLayoutByName(
-      const std::string& layout_name) = 0;
+  virtual bool SetCurrentKeyboardLayoutByName(const std::string& layout_name);
+
+  // Gets the current keyboard layout name.
+  const std::string GetCurrentKeyboardLayoutName() { return last_layout_; }
 
   // Sets the current keyboard layout again. We have to call the function every
   // time when "XI_HierarchyChanged" XInput2 event is sent to Chrome. See
   // xinput_hierarchy_changed_event_listener.h for details.
   virtual bool ReapplyCurrentKeyboardLayout() = 0;
 
   // Updates keyboard LEDs on all keyboards.
   // XKB asymmetrically propagates keyboard modifier indicator state changes to
   // slave keyboards. If the state change is initiated from a client to the
   // "core/master keyboard", XKB changes global state and pushes an indication
@@ skipping 50 matching lines @@
   std::string last_layout_;
 
  private:
   base::ObserverList<Observer> observers_;
 };
 
 }  // namespace input_method
 }  // namespace chromeos
 
 #endif  // UI_BASE_IME_CHROMEOS_IME_KEYBOARD_H_