Added support of relative mouse motion in Chromoting.

remoting/host/input_injector_linux.cc

Index: remoting/host/input_injector_linux.cc
diff --git a/remoting/host/input_injector_linux.cc b/remoting/host/input_injector_linux.cc
index cbb807bdc3a65aaed001f500244caaff0bc85517..53d13c5872f99923d2f19f1477e019a0f6ef0e4f 100644
--- a/remoting/host/input_injector_linux.cc
+++ b/remoting/host/input_injector_linux.cc
@@ -299,7 +299,14 @@ void InputInjectorLinux::Core::InjectMouseEvent(const MouseEvent& event) {
     return;
   }
 
-  if (event.has_x() && event.has_y()) {
+  if (event.has_delta_x() && event.has_delta_y()) {
+    latest_mouse_position_ = SkIPoint::Make(-1, -1);
+    VLOG(3) << "Moving mouse by " << event.delta_x() << "," << event.delta_y();
+    XTestFakeRelativeMotionEvent(display_, DefaultScreen(display_),
+                                 event.delta_x(), event.delta_y(),
+                                 CurrentTime);

[Wez, 2013/09/05 20:24:45]

nit: Filter out 0x0 movement?

[alexeypa (please no reviews), 2013/09/06 20:00:17]

Done.

+
+  } else if (event.has_x() && event.has_y()) {
     // Injecting a motion event immediately before a button release results in
     // a MotionNotify even if the mouse position hasn't changed, which confuses
     // apps which assume MotionNotify implies movement. See crbug.com/138075.