[Chromoting] Refactoring DesktopEnvironment and moving screen/audio recorders to ClientSession.

remoting/remoting.gyp

Index: remoting/remoting.gyp
diff --git a/remoting/remoting.gyp b/remoting/remoting.gyp
index e45ad63aa73bf16c654722948c941b91296cd8db..cc8ff0e11bb488759044160ebd709f029699b964 100644
--- a/remoting/remoting.gyp
+++ b/remoting/remoting.gyp
@@ -1288,6 +1288,8 @@
         'host/continue_window_win.cc',
         'host/desktop_environment.cc',
         'host/desktop_environment.h',
+        'host/desktop_environment_factory.cc',
+        'host/desktop_environment_factory.h',
         'host/differ.cc',
         'host/differ.h',
         'host/disconnect_window.h',
@@ -1355,8 +1357,6 @@
         'host/screen_recorder.h',
         'host/server_log_entry.cc',
         'host/server_log_entry.h',
-        'host/session_event_executor_win.cc',
-        'host/session_event_executor_win.h',
         'host/session_manager_factory.cc',
         'host/session_manager_factory.h',
         'host/signaling_connector.cc',
@@ -1383,6 +1383,10 @@
         'host/win/desktop.h',
         'host/win/scoped_thread_desktop.cc',
         'host/win/scoped_thread_desktop.h',
+        'host/win/session_desktop_environment_factory.cc',
+        'host/win/session_desktop_environment_factory.h',
+        'host/win/session_event_executor.cc',
+        'host/win/session_event_executor.h',
         'host/x_server_pixel_buffer.cc',
         'host/x_server_pixel_buffer.h',
       ],
@@ -1826,6 +1830,8 @@
         'host/client_session_unittest.cc',
         'host/differ_block_unittest.cc',
         'host/differ_unittest.cc',
+        'host/event_executor_fake.cc',
+        'host/event_executor_fake.h',
         'host/heartbeat_sender_unittest.cc',
         'host/host_key_pair_unittest.cc',
         'host/host_mock_objects.cc',