Removed task runners from the DesktopEnviroment interface and introduced ScreenControls/ClientSessionControl interfaces.

This CL removes all task runners that used to be passed to methods of DesktopEnviroment and DesktopEnviromentFactory interfaces. Instead each object implementing these interfaces receives the set of task runners it needs in the constructor. This change makes DesktopEnviroment and DesktopEnviromentFactory interfaces cleaner and easier to implement.

Added the ScreenControls interface used by the client session to change the screen resolution. Objects implementing ScreenControls are created by DesktopEnvironment::CreateScreenControls() method.

DesktopEnviromentFactory::Create() now receives a pointer to the ClientSessionControl interface providing a way to pause, resume, and disconnect the client session. It also receives notifications about the local mouse movements to temporarily block the remote input. The ClientSessionControl interface will be hooked up to the local impit monitor and the host UI once they will be moved to DesktopEnvironment.

BUG=104544

Review URL: https://chromiumcodereview.appspot.com/12879006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@190345 0039d316-1c4b-4281-b951-d872f2087c98