X11: Add TestDesktopScreenX11 to simulate mouse movement in ui tests

chrome/test/base/view_event_test_platform_part_default.cc

Index: chrome/test/base/view_event_test_platform_part_default.cc
diff --git a/chrome/test/base/view_event_test_platform_part_default.cc b/chrome/test/base/view_event_test_platform_part_default.cc
index 75050091c611d6c62a1c5e23890d07dfd50c670e..54497609886cb9e5b8ace1f4faaf0251b9bbc3f4 100644
--- a/chrome/test/base/view_event_test_platform_part_default.cc
+++ b/chrome/test/base/view_event_test_platform_part_default.cc
@@ -10,6 +10,10 @@
 #include "ui/display/screen.h"
 #include "ui/views/widget/desktop_aura/desktop_screen.h"
 
+#if !defined(OS_CHROMEOS) && defined(OS_LINUX)
+#include "ui/views/test/test_desktop_screen_x11.h"
+#endif
+
 namespace {
 
 // ViewEventTestPlatformPart implementation for Views, but non-CrOS.
@@ -18,8 +22,14 @@ class ViewEventTestPlatformPartDefault : public ViewEventTestPlatformPart {
   explicit ViewEventTestPlatformPartDefault(
       ui::ContextFactory* context_factory) {
 #if defined(USE_AURA)
+    DCHECK(!display::Screen::GetScreen());
+#if !defined(OS_CHROMEOS) && defined(OS_LINUX)
+    display::Screen::SetScreenInstance(
+        views::test::TestDesktopScreenX11::GetInstance());
+#else
     screen_.reset(views::CreateDesktopScreen());
     display::Screen::SetScreenInstance(screen_.get());
+#endif
     env_ = aura::Env::CreateInstance();
     env_->set_context_factory(context_factory);
 #endif