X11: Add TestDesktopScreenX11 to simulate mouse movement in ui tests

ui/views/widget/desktop_aura/desktop_screen_x11.h

Index: ui/views/widget/desktop_aura/desktop_screen_x11.h
diff --git a/ui/views/widget/desktop_aura/desktop_screen_x11.h b/ui/views/widget/desktop_aura/desktop_screen_x11.h
index 03f5c6255b03ac75a1684ac4c3fe3836ed4fc073..29298cdc72779bb4e46b4249ec524cff2b60a23e 100644
--- a/ui/views/widget/desktop_aura/desktop_screen_x11.h
+++ b/ui/views/widget/desktop_aura/desktop_screen_x11.h
@@ -14,6 +14,7 @@
 #include "ui/display/display_change_notifier.h"
 #include "ui/display/screen.h"
 #include "ui/events/platform/platform_event_dispatcher.h"
+#include "ui/gfx/geometry/point.h"
 #include "ui/gfx/x/x11_atom_cache.h"
 #include "ui/views/views_export.h"
 
@@ -102,6 +103,22 @@ class VIEWS_EXPORT DesktopScreenX11 : public display::Screen,
   DISALLOW_COPY_AND_ASSIGN(DesktopScreenX11);
 };
 
+class VIEWS_EXPORT TestDesktopScreenX11 : public DesktopScreenX11 {

[sky, 2016/09/08 23:41:24]

Document what this class does and why it's needed. Also, it should be in its own
header that is only built in tests.

[Tom (Use chromium acct), 2016/09/09 01:14:11]

Done.

+ public:
+  TestDesktopScreenX11();
+  ~TestDesktopScreenX11() override;
+
+  gfx::Point GetCursorScreenPoint() override;
+  void SetCursorScreenPoint(const gfx::Point& point);
+
+ private:
+  gfx::Point cursor_screen_point_;
+
+  DISALLOW_COPY_AND_ASSIGN(TestDesktopScreenX11);
+};
+
+VIEWS_EXPORT TestDesktopScreenX11* GetTestDesktopScreenX11();
+
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_SCREEN_X11_H_