Add APIs to the client plugin to re-map and trap key events.

remoting/client/key_event_mapper.cc

Index: remoting/client/key_event_mapper.cc
diff --git a/remoting/client/key_event_mapper.cc b/remoting/client/key_event_mapper.cc
new file mode 100644
index 0000000000000000000000000000000000000000..742fecacba867da1e8eeab3f5fc2732f4bf3fa23
--- /dev/null
+++ b/remoting/client/key_event_mapper.cc
@@ -0,0 +1,63 @@
+// Copyright (c) 2012 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.
+
+#include "remoting/client/key_event_mapper.h"
+
+#include "remoting/proto/event.pb.h"
+
+namespace remoting {
+
+KeyEventMapper::KeyEventMapper() {
+}
+
+KeyEventMapper::KeyEventMapper(InputStub* stub) : protocol::InputFilter(stub) {
+}
+
+KeyEventMapper::~KeyEventMapper() {
+}
+
+void KeyEventMapper::SetTrapCallback(KeyTrapCallback callback) {
+  trap_callback = callback;
+}
+
+void KeyEventMapper::TrapKey(uint32 usb_keycode, bool trap_key) {
+  if (trap_key) {
+    trapped_keys.insert(usb_keycode);
+  } else {
+    trapped_keys.erase(usb_keycode);
+  }
+}
+
+void KeyEventMapper::RemapKey(uint32 in_usb_keycode, uint32 out_usb_keycode) {
+  if (in_usb_keycode == out_usb_keycode) {
+    mapped_keys.erase(in_usb_keycode);
+  } else {
+    mapped_keys[in_usb_keycode] = out_usb_keycode;
+  }
+}
+
+void KeyEventMapper::InjectKeyEvent(const protocol::KeyEvent& event) {
+  if (event.has_usb_keycode()) {
+    // Deliver trapped keys to the callback, not the next stub.
+    if (!trap_callback.is_null() && event.has_pressed() &&
+        (trapped_keys.find(event.usb_keycode()) != trapped_keys.end())) {
+      trap_callback.Run(event.usb_keycode(), event.pressed());
+      return;
+    }
+
+    // Re-map mapped keys to the new value before passing them on.
+    std::map<uint32,uint32>::iterator mapped =
+        mapped_keys.find(event.usb_keycode());
+    if (mapped != mapped_keys.end()) {
+      protocol::KeyEvent new_event(event);
+      new_event.set_usb_keycode(mapped->second);
+      InputFilter::InjectKeyEvent(new_event);
+      return;
+    }
+  }
+
+  InputFilter::InjectKeyEvent(event);
+}
+
+}  // namespace remoting