Factor iOS native image loading into a utility function.

ios/chrome/browser/ui/ntp/new_tab_page_header_view.mm

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ios/chrome/browser/ui/ntp/new_tab_page_header_view.h"
 
 #include "base/logging.h"
 #include "base/mac/scoped_nsobject.h"
 #import "ios/chrome/browser/tabs/tab_model.h"
 #import "ios/chrome/browser/tabs/tab_model_observer.h"
 #import "ios/chrome/browser/ui/image_util.h"
 #import "ios/chrome/browser/ui/ntp/new_tab_page_header_constants.h"
 #import "ios/chrome/browser/ui/ntp/new_tab_page_toolbar_controller.h"
+#import "ios/chrome/browser/ui/uikit_ui_util.h"
 #import "ios/chrome/common/material_timing.h"
 #include "ios/chrome/grit/ios_theme_resources.h"
-#include "ui/base/resource/resource_bundle.h"
 #import "ui/gfx/ios/uikit_util.h"
 
 namespace {
 
 const CGFloat kOmniboxImageBottomInset = 1;
 const CGFloat kHintLabelSidePadding = 12;
 const CGFloat kMaxConstraintConstantDiff = 5;
 
 }  // namespace
 
@@ skipping 76 matching lines @@
 - (void)addViewsToSearchField:(UIView*)searchField {
   [searchField setBackgroundColor:[UIColor whiteColor]];
   UIImage* searchBorderImage =
       StretchableImageNamed(@"ntp_google_search_box", 12, 12);
   _searchBoxBorder.reset([[UIImageView alloc] initWithImage:searchBorderImage]);
   [_searchBoxBorder setFrame:[searchField bounds]];
   [_searchBoxBorder setAutoresizingMask:UIViewAutoresizingFlexibleWidth |
                                         UIViewAutoresizingFlexibleHeight];
   [searchField insertSubview:_searchBoxBorder atIndex:0];
 
-  ResourceBundle& rb = ResourceBundle::GetSharedInstance();
-  UIImage* fullBleedShadow =
-      rb.GetNativeImageNamed(IDR_IOS_TOOLBAR_SHADOW_FULL_BLEED).ToUIImage();
+  UIImage* fullBleedShadow = NativeImage(IDR_IOS_TOOLBAR_SHADOW_FULL_BLEED);
   _shadow.reset([[UIImageView alloc] initWithImage:fullBleedShadow]);
   CGRect shadowFrame = [searchField bounds];
   shadowFrame.origin.y =
       searchField.bounds.size.height - kOmniboxImageBottomInset;
   shadowFrame.size.height = fullBleedShadow.size.height;
   [_shadow setFrame:shadowFrame];
   [_shadow setUserInteractionEnabled:NO];
   [_shadow setAutoresizingMask:UIViewAutoresizingFlexibleWidth |
                                UIViewAutoresizingFlexibleTopMargin];
   [searchField addSubview:_shadow];
@@ skipping 47 matching lines @@
 }
 
 - (void)fadeOutShadow {
   [UIView animateWithDuration:ios::material::kDuration1
                    animations:^{
                      [_shadow setAlpha:0];
                    }];
 }
 
 @end