Introdcue AshWindowTreeHost and move ash/chrome specific code in WTH to ash.

ash/ash.gyp

Index: ash/ash.gyp
diff --git a/ash/ash.gyp b/ash/ash.gyp
index 0fc17cb5b42c859100ff88967d6adb90e694cb8d..9ceeb564f95f5faf3c9ccb86a4a2c50f032d5c9f 100644
--- a/ash/ash.gyp
+++ b/ash/ash.gyp
@@ -177,8 +177,8 @@
         'frame/frame_border_hit_test_controller.h',
         'frame/default_header_painter.cc',
         'frame/default_header_painter.h',
-	    'frame/frame_util.cc',
-	    'frame/frame_util.h',
+        'frame/frame_util.cc',
+        'frame/frame_util.h',
         'frame/header_painter.h',
         'frame/header_painter_util.cc',
         'frame/header_painter_util.h',
@@ -187,9 +187,15 @@
         'gpu_support_stub.h',
         'high_contrast/high_contrast_controller.cc',
         'high_contrast/high_contrast_controller.h',
-        'host/window_tree_host_factory.cc',
-        'host/window_tree_host_factory.h',
-        'host/window_tree_host_factory_win.cc',
+        'host/ash_window_tree_host.cc',
+        'host/ash_window_tree_host.h',
+        'host/ash_window_tree_host_ozone.cc',
+        'host/ash_window_tree_host_ozone.h',
+        'host/ash_window_tree_host_win.cc',
+        'host/ash_window_tree_host_win.h',
+        'host/ash_window_tree_host_x11.cc',
+        'host/ash_window_tree_host_x11.h',
+        'host/root_window_transformer.h',
         'ime/candidate_view.cc',
         'ime/candidate_view.h',
         'ime/candidate_window_view.cc',
@@ -680,6 +686,10 @@
             ['exclude', 'display/display_error_observer_chromeos.cc'],
             ['exclude', 'display/display_error_observer_chromeos.h'],
           ],
+        }, { # else: use_x11==1
+          'dependencies': [
+            '../build/linux/system.gyp:xfixes',
+           ],
         }],
         ['chromeos==1', {
           'dependencies': [