Only block internal touchpad and allow external mice to continue working in maximize mode.

ash/wm/maximize_mode/internal_input_device_list.h

Index: ash/wm/maximize_mode/internal_input_device_list.h
diff --git a/ash/wm/maximize_mode/internal_input_device_list.h b/ash/wm/maximize_mode/internal_input_device_list.h
new file mode 100644
index 0000000000000000000000000000000000000000..4f9fc706c90f3265f53dbfc99ae442f0a7930df7
--- /dev/null
+++ b/ash/wm/maximize_mode/internal_input_device_list.h
@@ -0,0 +1,33 @@
+// 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 ASH_WM_MAXIMIZE_MODE_INTERNAL_INPUT_DEVICE_LIST_H_
+#define ASH_WM_MAXIMIZE_MODE_INTERNAL_INPUT_DEVICE_LIST_H_
+
+#include <set>
+
+#include "base/macros.h"
+
+namespace ui {
+class Event;
+}
+
+namespace ash {
+
+// Identifies which input devices are internal and provides a helper function to
+// test if an input event came from an internal device.
+class InternalInputDeviceList {
+ public:
+  InternalInputDeviceList() {}
+  virtual ~InternalInputDeviceList() {}
+
+  virtual bool IsEventFromInternalDevice(const ui::Event* event) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(InternalInputDeviceList);
+};
+
+}  // namespace ash
+
+#endif  // ASH_WM_MAXIMIZE_MODE_INTERNAL_INPUT_DEVICE_LIST_H_