Adds a new constructor for gfx::Image on iOS.

ui/gfx/image/image.h

Index: ui/gfx/image/image.h
diff --git a/ui/gfx/image/image.h b/ui/gfx/image/image.h
index bf0d9b455fcd6d00c623b41b5d9875dee867ef5d..0677b3ede7bef1bc2a2fe37129fcb1f4607006cc 100644
--- a/ui/gfx/image/image.h
+++ b/ui/gfx/image/image.h
@@ -26,6 +26,7 @@
 #include <vector>
 
 #include "base/memory/ref_counted_memory.h"
+#include "base/memory/scoped_policy.h"
 #include "build/build_config.h"
 #include "ui/gfx/gfx_export.h"
 #include "ui/gfx/native_widget_types.h"
@@ -72,6 +73,10 @@ class GFX_EXPORT Image {
 #if defined(OS_IOS)
   // Does not retain |image|; expects to take ownership.
   explicit Image(UIImage* image);
+
+  // Retains argument according to |policy|.
+  Image(UIImage* image, base::scoped_policy::OwnershipPolicy policy);
+
 #elif defined(OS_MACOSX)
   // Does not retain |image|; expects to take ownership.
   // A single NSImage object can contain multiple bitmaps so there's no reason