Make Interaction Media Features MQ dynamic on Linux.

content/browser/renderer_host/input/input_device_change_observer.cc

 // Copyright 2017 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 "content/browser/renderer_host/input/input_device_change_observer.h"
 #include "base/trace_event/trace_event.h"
 #include "content/public/common/web_preferences.h"
 
 #if defined(OS_WIN)
 #include "ui/events/devices/input_device_observer_win.h"
+#elif defined(OS_LINUX)
+#include "ui/events/devices/device_data_manager.h"
 #endif
 
 namespace content {
 
 InputDeviceChangeObserver::InputDeviceChangeObserver(RenderViewHost* rvh) {
   render_view_host_ = rvh;
 #if defined(OS_WIN)
   ui::InputDeviceObserverWin::GetInstance()->AddObserver(this);
+#elif defined(OS_LINUX)
+  ui::DeviceDataManager::GetInstance()->AddObserver(this);

[sadrul, 2017/05/10 01:47:53]

I have left a comment in https://codereview.chromium.org/2690323002/#msg84

This should be:
 
#if defined(OS_WIN) || defined(OS_LINUX)
  ui::InputDeviceManager::GetInstance()->AddObserver(this);
#endif

 #endif
 }
 
 InputDeviceChangeObserver::~InputDeviceChangeObserver() {
 #if defined(OS_WIN)
   ui::InputDeviceObserverWin::GetInstance()->RemoveObserver(this);
+#elif defined(OS_LINUX)
+  ui::DeviceDataManager::GetInstance()->RemoveObserver(this);
 #endif
   render_view_host_ = nullptr;
 }
 
 void InputDeviceChangeObserver::OnTouchscreenDeviceConfigurationChanged() {
   NotifyRenderViewHost();
 }
 
 void InputDeviceChangeObserver::OnKeyboardDeviceConfigurationChanged() {
   NotifyRenderViewHost();
@@ skipping 16 matching lines @@
       prefs.available_pointer_types != available_pointer_types ||
       prefs.available_hover_types != available_hover_types;
 
   if (input_device_changed) {
     TRACE_EVENT0("input", "InputDeviceChangeObserver::NotifyRendererViewHost");
     render_view_host_->OnWebkitPreferencesChanged();
   }
 }
 
 }  // namespace content