Stop dispatching mouse move events for wheel scrolling in X11.

ui/events/x/events_x_unittest.cc

 // Copyright (c) 2012 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 <cstring>
 #include <set>
 
 #include <X11/extensions/XInput2.h>
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
@@ skipping 475 matching lines @@
       if (is_char) {
         KeyEventTestApi test_event(&key_event);
         test_event.set_is_char(true);
       }
       EXPECT_FALSE(key_event.flags() & ui::EF_IME_FABRICATED_KEY);
     }
   }
 }
 #endif
 
+TEST_F(EventsXTest, IgnoresMotionEventForMouseWheelScroll) {
+  int device_id = 1;
+  std::vector<int> devices;
+  devices.push_back(device_id);
+  ui::SetUpPointerDevicesForTest(devices);
+
+  ScopedXI2Event xev;
+  xev.InitScrollEvent(device_id, 1, 2, 3, 4, 1);
+  // We shouldn't produce a mouse move event on a mouse wheel
+  // scroll. These events are only produced for some mice.
+  EXPECT_EQ(ui::ET_UNKNOWN, ui::EventTypeFromNative(xev));
+}
+
 }  // namespace ui