Avoid crashing when an ImageSkia has no representations and is converted to SkBitmap.

ui/gfx/image/image_skia.h

Index: ui/gfx/image/image_skia.h
diff --git a/ui/gfx/image/image_skia.h b/ui/gfx/image/image_skia.h
index fffae7a54d0ca4c748fca8af5f222c5721cb59aa..38e6e7a57f674dba44ba47a1785abc07ec40ee40 100644
--- a/ui/gfx/image/image_skia.h
+++ b/ui/gfx/image/image_skia.h
@@ -113,7 +113,7 @@ class UI_EXPORT ImageSkia {
   // This function should only be used in unittests and on platforms which do
   // not support scale factors other than 1x.
   // TODO(pkotwicz): Return null SkBitmap when the object has no 1x bitmap.
-  const SkBitmap* bitmap() const;
+  const SkBitmap* bitmap() const { return &operator SkBitmap&(); }
 
   // Returns a vector with the image reps contained in this object.
   // There is no guarantee that this will return all images rep for