Remove docked windows entirely in M59.

ash/BUILD.gn

Index: ash/BUILD.gn
diff --git a/ash/BUILD.gn b/ash/BUILD.gn
index 7b1de9d088e18db146a2b9f015312d29b13c4f53..d2cf900b489a979b17c6713d41538b40620b2f7a 100644
--- a/ash/BUILD.gn
+++ b/ash/BUILD.gn
@@ -459,11 +459,6 @@ component("ash") {
     "common/wm/default_state.h",
     "common/wm/default_window_resizer.cc",
     "common/wm/default_window_resizer.h",
-    "common/wm/dock/docked_window_layout_manager.cc",
-    "common/wm/dock/docked_window_layout_manager.h",
-    "common/wm/dock/docked_window_layout_manager_observer.h",
-    "common/wm/dock/docked_window_resizer.cc",
-    "common/wm/dock/docked_window_resizer.h",
     "common/wm/drag_details.cc",
     "common/wm/drag_details.h",
     "common/wm/focus_rules.cc",
@@ -1236,8 +1231,6 @@ source_set("common_unittests") {
     "test/ash_test_helper_unittest.cc",
     "tooltips/tooltip_controller_unittest.cc",
     "wm/ash_focus_rules_unittest.cc",
-    "wm/dock/docked_window_layout_manager_unittest.cc",
-    "wm/dock/docked_window_resizer_unittest.cc",
     "wm/immersive_fullscreen_controller_unittest.cc",
     "wm/lock_state_controller_unittest.cc",
     "wm/maximize_mode/accelerometer_test_data_literals.cc",