Remove calls to IsRunningSequenceOnCurrentThread() in wallpaper API.

components/wallpaper/wallpaper_manager_base.h

Index: components/wallpaper/wallpaper_manager_base.h
diff --git a/components/wallpaper/wallpaper_manager_base.h b/components/wallpaper/wallpaper_manager_base.h
index 69ca35f6099d602ad67a6af228fc0678c38888d1..a734d2f5f03983d4a2df2f4029a483cd142328fb 100644
--- a/components/wallpaper/wallpaper_manager_base.h
+++ b/components/wallpaper/wallpaper_manager_base.h
@@ -80,6 +80,10 @@ struct WALLPAPER_EXPORT WallpaperInfo {
   }
 };
 
+// Asserts that the current task is sequenced with any other task that calls
+// this.
+void WALLPAPER_EXPORT AssertCalledOnWallpaperSequence();
+
 class WallpaperManagerBrowserTest;
 
 // Name of wallpaper sequence token.