Added support of relative mouse motion in Chromoting.

remoting/host/input_injector_linux.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/host/input_injector.h"
 
 #include <X11/Xlib.h>
 #include <X11/extensions/XTest.h>
 #include <X11/extensions/XInput.h>
 
@@ skipping 281 matching lines @@
   }
 }
 
 void InputInjectorLinux::Core::InjectMouseEvent(const MouseEvent& event) {
   if (!task_runner_->BelongsToCurrentThread()) {
     task_runner_->PostTask(FROM_HERE,
                            base::Bind(&Core::InjectMouseEvent, this, event));
     return;
   }
 
-  if (event.has_x() && event.has_y()) {
+  if (event.has_delta_x() &&
+      event.has_delta_y() &&
+      (event.delta_x() != 0 || event.delta_y() != 0)) {
+    latest_mouse_position_ = SkIPoint::Make(-1, -1);
+    VLOG(3) << "Moving mouse by " << event.delta_x() << "," << event.delta_y();
+    XTestFakeRelativeMotionEvent(display_,
+                                 event.delta_x(), event.delta_y(),
+                                 CurrentTime);
+
+  } 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.
     bool inject_motion = true;
     SkIPoint new_mouse_position(SkIPoint::Make(event.x(), event.y()));
     if (event.has_button() && event.has_button_down() && !event.button_down()) {
       if (new_mouse_position == latest_mouse_position_)
         inject_motion = false;
     }
 
@@ skipping 194 matching lines @@
     scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
     scoped_refptr<base::SingleThreadTaskRunner> ui_task_runner) {
   scoped_ptr<InputInjectorLinux> injector(
       new InputInjectorLinux(main_task_runner));
   if (!injector->Init())
     return scoped_ptr<InputInjector>();
   return injector.PassAs<InputInjector>();
 }
 
 }  // namespace remoting