aura: Unify WindowTreeHost for some platforms

ui/platform_window/win/win_window.cc

Index: ui/platform_window/win/win_window.cc
diff --git a/ui/platform_window/win/win_window.cc b/ui/platform_window/win/win_window.cc
index 0c63a6cb931f5dc77327ccd5b88021292411a0c8..9792751670bfac1d4172044fbfa498d963b0cb11 100644
--- a/ui/platform_window/win/win_window.cc
+++ b/ui/platform_window/win/win_window.cc
@@ -6,6 +6,7 @@
 
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string16.h"
+#include "ui/base/cursor/cursor_loader_win.h"
 #include "ui/events/event.h"
 #include "ui/events/event_utils.h"
 #include "ui/gfx/win/msg_util.h"
@@ -107,7 +108,15 @@ void WinWindow::Minimize() {}
 
 void WinWindow::Restore() {}
 
-void WinWindow::SetCursor(PlatformCursor cursor) {}
+void WinWindow::SetCursor(PlatformCursor cursor) {
+  // Custom web cursors are handled directly.
+  if (cursor == ui::kCursorCustom)
+    return;
+
+  ui::CursorLoaderWin cursor_loader;
+  cursor_loader.SetPlatformCursor(&cursor);
+  ::SetCursor(cursor.platform());
+}
 
 void WinWindow::MoveCursorTo(const gfx::Point& location) {}