[AR][IOS] Fixes typo in constant

Bug: 958938
Change-Id: Ia6dd28f199732906327a2ca6b7d2d45053690ea9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1600626Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Moe Ahmadi <mahmadi@chromium.org>
Auto-Submit: Moe Ahmadi <mahmadi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#659724}

ios/chrome/browser/download/usdz_mime_type.cc

@@ -7,7 +7,7 @@
 #include "base/files/file_path.h"
 #include "base/strings/utf_string_conversions.h"
 
-char kUsdzFileExntension[] = ".usdz";
+char kUsdzFileExtension[] = ".usdz";
 char kUsdzMimeType[] = "model/vnd.usdz+zip";
 char kLegacyUsdzMimeType[] = "model/usd";
 char kLegacyPixarUsdzMimeType[] = "model/vnd.pixar.usd";
@@ -17,5 +17,5 @@ bool IsUsdzFileFormat(const std::string& mime_type,
   return mime_type == kUsdzMimeType || mime_type == kLegacyUsdzMimeType ||
          mime_type == kLegacyPixarUsdzMimeType ||
          base::FilePath(base::UTF16ToUTF8(suggested_filename))
-             .MatchesExtension(kUsdzFileExntension);
+             .MatchesExtension(kUsdzFileExtension);
 }