Adds special support to the device manager for keyboards devices.

ui/events/BUILD.gn

Index: ui/events/BUILD.gn
diff --git a/ui/events/BUILD.gn b/ui/events/BUILD.gn
index c697e548894f62ae1deb14c02a9315a83080f572..395dab03934121935d5aa54004d928027df22985 100644
--- a/ui/events/BUILD.gn
+++ b/ui/events/BUILD.gn
@@ -32,6 +32,10 @@ component("events_base") {
     "gestures/fling_curve.h",
     "gestures/gesture_configuration.cc",
     "gestures/gesture_configuration.h",
+    "input_device.cc",
+    "input_device.h",
+    "keyboard_device.cc",
+    "keyboard_device.h",
     "keycodes/keyboard_code_conversion.cc",
     "keycodes/keyboard_code_conversion.h",
     "keycodes/keyboard_code_conversion_android.cc",
@@ -293,6 +297,7 @@ test("events_unittests") {
     "keycodes/dom4/keycode_converter_unittest.cc",
     "latency_info_unittest.cc",
     "platform/platform_event_source_unittest.cc",
+    "x/device_data_manager_x11_unittest.cc",
     "x/events_x_unittest.cc",
   ]
 
@@ -315,6 +320,7 @@ test("events_unittests") {
     deps += [ "//ui/gfx/x" ]
   } else {
     sources -= [
+      "x/device_data_manager_x11_unittest.cc",
       "x/events_x_unittest.cc",
     ]
   }