X11: Add TestDesktopScreenX11 to simulate mouse movement in ui tests

chrome/test/base/in_process_browser_test.cc

Index: chrome/test/base/in_process_browser_test.cc
diff --git a/chrome/test/base/in_process_browser_test.cc b/chrome/test/base/in_process_browser_test.cc
index 2c82ab0033a69fc650ad4e96c2b2a065f85f255d..d774d934c2712bd53e3da1c07b9fcc8bc81ed8ef 100644
--- a/chrome/test/base/in_process_browser_test.cc
+++ b/chrome/test/base/in_process_browser_test.cc
@@ -86,6 +86,10 @@
 #include "chrome/test/base/default_ash_event_generator_delegate.h"
 #endif
 
+#if !defined(OS_CHROMEOS) && defined(OS_LINUX)
+#include "ui/views/widget/desktop_aura/desktop_screen_x11.h"
+#endif
+
 namespace {
 
 // Passed as value of kTestType.
@@ -222,7 +226,10 @@ void InProcessBrowserTest::SetUp() {
     command_line->AppendSwitchASCII(ash::switches::kAshHostWindowBounds,
                                     "0+0-1280x800");
   }
-#endif  // defined(OS_CHROMEOS)
+#elif defined(OS_LINUX)
+  DCHECK(!display::Screen::GetScreen());
+  display::Screen::SetScreenInstance(views::GetTestDesktopScreenX11());
+#endif
 
   // Always use a mocked password storage if OS encryption is used (which is
   // when anything sensitive gets stored, including Cookies). Without this on