Adds WmWindow and converts WindowState to use it

ash/wm/drag_details.cc

Index: ash/wm/drag_details.cc
diff --git a/ash/wm/drag_details.cc b/ash/wm/drag_details.cc
index 67bbedc123fb1aa41b546728bd0821df115eca8d..9c293bb4decbf1337a4fd54900b265437a7e16cf 100644
--- a/ash/wm/drag_details.cc
+++ b/ash/wm/drag_details.cc
@@ -4,6 +4,7 @@
 
 #include "ash/wm/drag_details.h"
 
+#include "ash/wm/common/wm_window.h"
 #include "ash/wm/window_resizer.h"
 #include "ui/aura/window.h"
 #include "ui/base/hit_test.h"
@@ -41,14 +42,14 @@ int GetSizeChangeDirectionForWindowComponent(int window_component) {
 
 }  // namespace
 
-DragDetails::DragDetails(aura::Window* window,
+DragDetails::DragDetails(wm::WmWindow* window,
                          const gfx::Point& location,
                          int window_component,
                          aura::client::WindowMoveSource source)
-    : initial_state_type(wm::GetWindowState(window)->GetStateType()),
-      initial_bounds_in_parent(window->bounds()),
+    : initial_state_type(window->GetWindowState()->GetStateType()),
+      initial_bounds_in_parent(window->GetBounds()),
       initial_location_in_parent(location),
-      initial_opacity(window->layer()->opacity()),
+      initial_opacity(window->GetLayer()->opacity()),
       window_component(window_component),
       bounds_change(
           WindowResizer::GetBoundsChangeForWindowComponent(window_component)),
@@ -59,9 +60,9 @@ DragDetails::DragDetails(aura::Window* window,
           GetSizeChangeDirectionForWindowComponent(window_component)),
       is_resizable(bounds_change != WindowResizer::kBoundsChangeDirection_None),
       source(source),
-      should_attach_to_shelf(window->type() == ui::wm::WINDOW_TYPE_PANEL &&
-                             wm::GetWindowState(window)->panel_attached()) {
-  wm::WindowState* window_state = wm::GetWindowState(window);
+      should_attach_to_shelf(window->GetType() == ui::wm::WINDOW_TYPE_PANEL &&
+                             window->GetWindowState()->panel_attached()) {
+  wm::WindowState* window_state = window->GetWindowState();
   if ((window_state->IsNormalOrSnapped() || window_state->IsDocked()) &&
       window_state->HasRestoreBounds() &&
       window_component == HTCAPTION) {