Factor iOS native image loading into a utility function.

ios/chrome/browser/ui/uikit_ui_util.mm

Index: ios/chrome/browser/ui/uikit_ui_util.mm
diff --git a/ios/chrome/browser/ui/uikit_ui_util.mm b/ios/chrome/browser/ui/uikit_ui_util.mm
index 238456844a0859bd8f40a39b241afca7fc847dbe..b82122d93f614177b8041e4a5c47c1772f508711 100644
--- a/ios/chrome/browser/ui/uikit_ui_util.mm
+++ b/ios/chrome/browser/ui/uikit_ui_util.mm
@@ -16,10 +16,12 @@
 #include "base/logging.h"
 #include "base/mac/foundation_util.h"
 #include "ios/chrome/browser/experimental_flags.h"
+#include "ios/chrome/browser/ui/rtl_geometry.h"
 #include "ios/chrome/browser/ui/ui_util.h"
 #include "ios/web/public/web_thread.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/l10n/l10n_util_mac.h"
+#include "ui/base/resource/resource_bundle.h"
 #include "ui/gfx/ios/uikit_util.h"
 #include "ui/gfx/scoped_cg_context_save_gstate_mac.h"
 
@@ -225,6 +227,19 @@ BOOL ImageHasAlphaChannel(UIImage* image) {
   }
 }
 
+UIImage* NativeReversableImage(int imageID, BOOL reversable) {
+  DCHECK(imageID);
+  ResourceBundle& rb = ResourceBundle::GetSharedInstance();
+  UIImage* image = rb.GetNativeImageNamed(imageID).ToUIImage();
+  return (reversable && UseRTLLayout())
+             ? [image imageFlippedForRightToLeftLayoutDirection]
+             : image;
+}
+
+UIImage* NativeImage(int imageID) {
+  return NativeReversableImage(imageID, NO);

[noyau (Ping after 24h), 2017/01/02 10:11:32]

Late driveby: Will this now reverse all images if UseRTLLayout() is true,
whereas before only the ones explicitely reversable were reversed?

[marq (ping after 24h), 2017/01/09 09:46:14]

NativeImage(image_id) will never reverse the image.

NativeReversableImage(image_id, YES) will reverse the image if RTLLayout() is
true; this (passing in YES) is how images are marked as explicitly reversible.

(I should fix the spelling of 'Reversable', however).

+}
+
 UIImage* ResizeImage(UIImage* image,
                      CGSize targetSize,
                      ProjectionMode projectionMode) {