Move LowerCaseEqualsASCII to base namespace

ios/chrome/browser/chrome_url_util.mm

 // Copyright 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/chrome_url_util.h"
 
 #import <UIKit/UIKit.h>
 
 #include "base/logging.h"
 #include "base/mac/scoped_block.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/strings/string_util.h"
 #include "base/strings/sys_string_conversions.h"
 #include "ios/chrome/browser/chrome_url_constants.h"
 #import "ios/net/url_scheme_util.h"
 #include "ios/public/provider/chrome/browser/chrome_browser_provider.h"
 #include "url/gurl.h"
 
 bool UrlIsExternalFileReference(const GURL& url) {
   return url.SchemeIs(ios::GetChromeBrowserProvider()->GetChromeUIScheme()) &&
-         LowerCaseEqualsASCII(url.host(), kChromeUIExternalFileHost);
+         base::LowerCaseEqualsASCII(url.host(), kChromeUIExternalFileHost);
 }
 
 NSURL* UrlToLaunchChrome() {
   // Determines the target URL scheme that will launch Chrome.
   NSString* scheme = [[ChromeAppConstants sharedInstance] getBundleURLScheme];
   return [NSURL URLWithString:[NSString stringWithFormat:@"%@://", scheme]];
 }
 
 NSURL* UrlOfChromeAppIcon(int width, int height) {
   NSString* url =
@@ skipping 61 matching lines @@
 
 - (void)setCallbackSchemeForTesting:(NSString*)scheme {
   _callbackScheme.reset([scheme copy]);
 }
 
 - (void)setAppIconURLProviderForTesting:(AppIconURLProvider)block {
   _appIconURLProvider.reset(block, base::scoped_policy::RETAIN);
 }
 
 @end