Factor iOS native image loading into a utility function.

ios/chrome/browser/ui/infobars/infobar_view.mm

 // Copyright (c) 2012 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/infobars/infobar_view.h"
 
 #import <CoreGraphics/CoreGraphics.h>
 #import <QuartzCore/QuartzCore.h>
 
 #include "base/format_macros.h"
@@ skipping 640 matching lines @@
   shadowY = -[shadow_ image].size.height;  // Shadow above the infobar.
   [shadow_ setFrame:CGRectMake(0, shadowY, self.bounds.size.width,
                                [shadow_ image].size.height)];
   [shadow_ setAutoresizingMask:UIViewAutoresizingFlexibleWidth];
 }
 
 - (void)addCloseButtonWithTag:(NSInteger)tag
                        target:(id)target
                        action:(SEL)action {
   DCHECK(!closeButton_);
-  // TODO(jeanfrancoisg): Add IDR_ constant and use GetNativeImageNamed().
-  // crbug/228611
+  // TODO(crbug/228611): Add IDR_ constant and use GetNativeImageNamed().
   NSString* imagePath =
       [[NSBundle mainBundle] pathForResource:@"infobar_close" ofType:@"png"];
   UIImage* image = [UIImage imageWithContentsOfFile:imagePath];
   closeButton_.reset([[UIButton buttonWithType:UIButtonTypeCustom] retain]);
   [closeButton_ setExclusiveTouch:YES];
   [closeButton_ setImage:image forState:UIControlStateNormal];
   [closeButton_ addTarget:target
                    action:action
          forControlEvents:UIControlEventTouchUpInside];
   [closeButton_ setTag:tag];
@@ skipping 270 matching lines @@
 
 - (CGFloat)buttonMargin {
   return kButtonMargin;
 }
 
 - (const std::vector<std::pair<NSUInteger, NSRange>>&)linkRanges {
   return linkRanges_;
 }
 
 @end