cheets: implement cros side of WallpaperManagerService.

chrome/browser/chromeos/arc/arc_service_launcher.h

Index: chrome/browser/chromeos/arc/arc_service_launcher.h
diff --git a/chrome/browser/chromeos/arc/arc_service_launcher.h b/chrome/browser/chromeos/arc/arc_service_launcher.h
index 7d912bbb5dc1bfcd7f89bd5841e078a36949af1a..03fc8752b463d15742aaba3fa0f31696f6f1042f 100644
--- a/chrome/browser/chromeos/arc/arc_service_launcher.h
+++ b/chrome/browser/chromeos/arc/arc_service_launcher.h
@@ -12,6 +12,8 @@
 
 namespace arc {
 
+class ArcWallpaperHandler;
+
 // Detects ARC availability and launches ARC bridge service.
 class ArcServiceLauncher {
  public:
@@ -23,6 +25,7 @@ class ArcServiceLauncher {
 
  private:
   std::unique_ptr<ArcServiceManager> arc_service_manager_;
+  std::unique_ptr<ArcWallpaperHandler> arc_wallpaper_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcServiceLauncher);
 };