Listen to XI_HierarchyChanged events and call setxkbmap when needed.

chrome/browser/chromeos/xinput_hierarchy_changed_event_listener.h

Index: chrome/browser/chromeos/xinput_hierarchy_changed_event_listener.h
diff --git a/chrome/browser/chromeos/xinput_hierarchy_changed_event_listener.h b/chrome/browser/chromeos/xinput_hierarchy_changed_event_listener.h
new file mode 100644
index 0000000000000000000000000000000000000000..7c37ac3769e15a1899e5b2fb16e18d37ba5fa0f6
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+++ b/chrome/browser/chromeos/xinput_hierarchy_changed_event_listener.h
@@ -0,0 +1,64 @@
+// Copyright (c) 2011 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 CHROME_BROWSER_CHROMEOS_XINPUT_HIERARCHY_CHANGED_EVENT_LISTENER_H_
+#define CHROME_BROWSER_CHROMEOS_XINPUT_HIERARCHY_CHANGED_EVENT_LISTENER_H_
+#pragma once
+
+// TODO(yusukes): Remove the #if once the ARM bot (crbug.com/84694) is fixed.
+#if defined(HAVE_XINPUT2)
+
+#include <gdk/gdk.h>
+
+#include "base/memory/singleton.h"
+#include "base/message_loop.h"
+
+typedef union _XEvent XEvent;
+
+namespace chromeos {
+
+// XInputHierarchyChangedEventListener listens for an XI_HierarchyChanged event,
+// which is sent to Chrome when X detects a system or USB keyboard (or mouse),
+// then tells X to change the current XKB keyboard layout. Start by just calling
+// instance() to get it going.
+class XInputHierarchyChangedEventListener : public MessageLoopForUI::Observer {
+ public:
+  static XInputHierarchyChangedEventListener* GetInstance();
+
+  void Stop();
+
+ private:
+  // Defines the delete on exit Singleton traits we like.  Best to have this
+  // and const/dest private as recommended for Singletons.
+  friend struct DefaultSingletonTraits<XInputHierarchyChangedEventListener>;
+
+  XInputHierarchyChangedEventListener();
+  virtual ~XInputHierarchyChangedEventListener();
+
+  // When TOUCH_UI is not defined, WillProcessXEvent() will not be called
+  // automatically. We have to call the function manually by adding the Gdk
+  // event filter.
+  static GdkFilterReturn GdkEventFilter(GdkXEvent* gxevent,
+                                        GdkEvent* gevent,
+                                        gpointer data);
+
+  // MessageLoopForUI::Observer overrides.
+  virtual void WillProcessEvent(GdkEvent* event) OVERRIDE {}
+  virtual void DidProcessEvent(GdkEvent* event) OVERRIDE {}
+  virtual bool WillProcessXEvent(XEvent* xevent)
+#if defined(TOUCH_UI)
+    OVERRIDE
+#endif
+    ;
+
+  bool stopped_;
+  int xiopcode_;
+
+  DISALLOW_COPY_AND_ASSIGN(XInputHierarchyChangedEventListener);
+};
+
+}  // namespace chromeos
+
+#endif
+#endif  // CHROME_BROWSER_CHROMEOS_XINPUT_HIERARCHY_CHANGED_EVENT_LISTENER_H_