Make Interaction Media Features MQ dynamic on Windows.

content/browser/renderer_host/render_view_host_impl.h

Index: content/browser/renderer_host/render_view_host_impl.h
diff --git a/content/browser/renderer_host/render_view_host_impl.h b/content/browser/renderer_host/render_view_host_impl.h
index bcc702b2b4f44508d50894ed828b23dd9ebd3369..99f293f70d6425145b00ac470c795817535b8205 100644
--- a/content/browser/renderer_host/render_view_host_impl.h
+++ b/content/browser/renderer_host/render_view_host_impl.h
@@ -20,6 +20,7 @@
 #include "base/macros.h"
 #include "base/process/kill.h"
 #include "build/build_config.h"
+#include "content/browser/renderer_host/input/input_device_change_observer.h"
 #include "content/browser/renderer_host/render_widget_host_impl.h"
 #include "content/browser/renderer_host/render_widget_host_owner_delegate.h"
 #include "content/browser/site_instance_impl.h"
@@ -324,6 +325,9 @@ class CONTENT_EXPORT RenderViewHostImpl : public RenderViewHost,
   // closed.
   std::unique_ptr<TimeoutMonitor> close_timeout_;
 
+  // This monitors input changes so they can be reflected to the interaction MQ.
+  std::unique_ptr<InputDeviceChangeObserver> input_device_change_observer_;
+
   bool updating_web_preferences_;
 
   bool render_view_ready_on_process_launch_;