Access ChromotingHost::clients_ only on network thread.

Previously ChromotingHost was doing some work on the main thread and
some on the network thread. |clients_| and some other members were
accessed without lock on both of these threads. Moved most of the
ChromotingHost activity to the network thread to avoid possible
race conditions.

BUG=96325
TEST=Chromoting works

Review URL: http://codereview.chromium.org/8495024

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@109556 0039d316-1c4b-4281-b951-d872f2087c98
 void ClientSession::LocalMouseMoved(const SkIPoint& mouse_pos) {
  std::list<SkIPoint>::iterator found_position =
      std::find(injected_mouse_positions_.begin(),
                injected_mouse_positions_.end(), mouse_pos);
  if (found_position != injected_mouse_positions_.end()) {
    injected_mouse_positions_.erase(injected_mouse_positions_.begin(),
                                    ++found_position);
  } else {
    latest_local_input_time_ = base::Time::Now();
  }
}

 void ClientSession::LocalMouseMoved(const SkIPoint& mouse_pos) {
  std::list<SkIPoint>::iterator found_position =
      std::find(injected_mouse_positions_.begin(),
                injected_mouse_positions_.end(), mouse_pos);
  if (found_position != injected_mouse_positions_.end()) {
    injected_mouse_positions_.erase(injected_mouse_positions_.begin(),
                                    ++found_position);
  } else {
    latest_local_input_time_ = base::Time::Now();
  }
}
