X11: Add TestDesktopScreenX11 to simulate mouse movement in ui tests

chrome/browser/ui/views/tabs/tab_drag_controller_interactive_uitest.cc

Index: chrome/browser/ui/views/tabs/tab_drag_controller_interactive_uitest.cc
diff --git a/chrome/browser/ui/views/tabs/tab_drag_controller_interactive_uitest.cc b/chrome/browser/ui/views/tabs/tab_drag_controller_interactive_uitest.cc
index 3e675a870289aad8567f32d8d3fc9bd317193a1a..1e410be19d0b845acb669b79bd134ac2bdd56b21 100644
--- a/chrome/browser/ui/views/tabs/tab_drag_controller_interactive_uitest.cc
+++ b/chrome/browser/ui/views/tabs/tab_drag_controller_interactive_uitest.cc
@@ -673,15 +673,9 @@ void DragToSeparateWindowStep2(DetachToBrowserTabDragControllerTest* test,
 
 }  // namespace
 
-#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
-// TODO: Disabled as mouse isn't updated propertly, http://crbug.com/640741.
-#define MAYBE_DragToSeparateWindow DISABLED_DragToSeparateWindow
-#else
-#define MAYBE_DragToSeparateWindow DragToSeparateWindow
-#endif
 // Creates two browsers, drags from first into second.
 IN_PROC_BROWSER_TEST_P(DetachToBrowserTabDragControllerTest,
-                       MAYBE_DragToSeparateWindow) {
+                       DragToSeparateWindow) {
   TabStrip* tab_strip = GetTabStripForBrowser(browser());
 
   // Add another tab to browser().