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

remoting/host/linux/x_server_key_mapper.h

Index: remoting/host/linux/x_server_key_mapper.h
diff --git a/remoting/host/linux/x_server_key_mapper.h b/remoting/host/linux/x_server_key_mapper.h
new file mode 100644
index 0000000000000000000000000000000000000000..62cbde053e607e7bafc97d205c71ddc3660b1c11
--- /dev/null
+++ b/remoting/host/linux/x_server_key_mapper.h
@@ -0,0 +1,61 @@
+// 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_X_SERVER_KEY_MAPPER_H_
+#define REMOTING_HOST_LINUX_X_SERVER_KEY_MAPPER_H_
+
+#include <stdint.h>
+#include <X11/Xlib.h>
+
+#include <vector>
+
+#include "base/macros.h"
+#include "base/time/time.h"
+
+namespace remoting {
+
+class KeyboardInterface;
+
+/**

[Sergey Ulanov, 2016/09/21 19:59:23]

Use C++ style comments please: //

[Yuwei, 2016/09/23 01:40:37]

Done.

+ * This is a helper class for assigning unused keycodes to characters. When all
+ * keycodes are used, newly added character will take the keycode of the oldest
+ * character.
+ * When the key mapper is destructed, all keycodes used by the mapper will be
+ * reset to map NoSymbol.
+ * The key mapper must be used on single thread thread.
+ */
+class XServerKeyMapper {

[Sergey Ulanov, 2016/09/21 19:59:23]

X11KeyMapper?

[Yuwei, 2016/09/23 01:40:37]

Done.

+ public:
+  struct MapResult {
+    bool success;
+
+    // |keycode| will only be valid if success == true.

[Sergey Ulanov, 2016/09/21 19:59:23]

Maybe remove success and use keycode=0 to indicate failure?

[Yuwei, 2016/09/23 01:40:37]

Just think could keycode 0 be used for mapping... Since now we also have
|modifiers| I think having an explicit success field may be clearer...

Just removed this comment.

+    uint32_t keycode;
+
+    // If success == false and |retry_after| is not zero, user may retry
+    // AddNewCharacter() after |retry_after| has elapsed.
+    base::TimeDelta retry_after;
+  };
+
+  explicit XServerKeyMapper(KeyboardInterface* keyboard);
+  ~XServerKeyMapper();
+
+  // |code_point|: The Unicode code point for the character.
+  // Returns the result of the mapping attempt.
+  MapResult AddNewCharacter(uint32_t code_point);
+
+ private:
+  struct KeyInfo;
+
+  KeyboardInterface* keyboard_;
+
+  std::vector<KeyInfo> available_keycodes_;
+  int current_keycode_index_ = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(XServerKeyMapper);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_LINUX_X_SERVER_KEY_MAPPER_H_