[Remoting Host] Handle text event characters that are not presented on the keyboard

remoting/host/linux/x11_keyboard.h

Index: remoting/host/linux/x11_keyboard.h
diff --git a/remoting/host/linux/x11_keyboard.h b/remoting/host/linux/x11_keyboard.h
new file mode 100644
index 0000000000000000000000000000000000000000..992c908f7d9af30a357e2ab9508f76d48384a1a2
--- /dev/null
+++ b/remoting/host/linux/x11_keyboard.h
@@ -0,0 +1,55 @@
+// Copyright 2016 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 REMOTING_HOST_LINUX_X11_KEYBOARD_H_
+#define REMOTING_HOST_LINUX_X11_KEYBOARD_H_
+
+#include <stdint.h>
+
+#include <vector>
+
+#include "base/macros.h"
+
+namespace remoting {
+
+// An interface for accessing the keyboard and changing the keyboard layout.
+// An implementation is allowed to delay processing a request until Flush() or
+// Sync() is called.
+class X11Keyboard {
+ public:
+  virtual ~X11Keyboard() {}
+
+  // Returns a vector of key codes that are not being mapped to a code point.
+  virtual std::vector<uint32_t> GetUnusedKeycodes() = 0;
+
+  // Simulates a key press with the given |keycode| and |modifiers|. Note that
+  // the application receiving the key press can decide whether or how the key
+  // press is interpreted into a character.
+  virtual void PressKey(uint32_t keycode, uint32_t modifiers) = 0;
+
+  // Finds a keycode and set of modifiers that generate character with the
+  // specified |code_point|. Returns true if the key code is successfully found.
+  // If the keycode is not found, |keycode| and |modifiers| will not be
+  // affected.
+  virtual bool FindKeycode(uint32_t code_point,
+                           uint32_t* keycode,
+                           uint32_t* modifiers) = 0;
+
+  // Change the key mapping such that pressing |keycode| will output the
+  // character of |code_point|.
+  virtual bool ChangeKeyMapping(uint32_t keycode, uint32_t code_point) = 0;
+
+  // Flushes all requests but don't wait for processing the requests.
+  virtual void Flush() = 0;
+
+  // Flushes all requests and wait until all requests are processed.
+  virtual void Sync() = 0;
+
+ protected:
+  X11Keyboard() {}
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_LINUX_X11_KEYBOARD_H_