[ios] Stop defining DIR_LOCALES on iOS

The value returned by DIR_LOCALES on iOS was incorrect and never used
(it is only used in ResourceBundle::GetLocaleFilePath which is overridden
on both iOS and macOS).

Stop using DIR_MODULE in ui/base/test/run_all_unittests.cc on iOS as
the resources should instead be loaded relative to DIR_ASSETS (and in
fact DIR_MODULE will soon be undefined on iOS).

Bug: 1257402
Change-Id: Iae3d43e2b036732afb60ba3d3d62d35839b684d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4614430
Reviewed-by: Scott Violet <[email protected]>
Commit-Queue: Sylvain Defresne <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1159577}
diff --git a/ui/base/ui_base_paths.h b/ui/base/ui_base_paths.h
index 29c22461..1e53a85 100644
--- a/ui/base/ui_base_paths.h
+++ b/ui/base/ui_base_paths.h
@@ -16,7 +16,9 @@
 enum {
   PATH_START = 3000,
 
+#if !BUILDFLAG(IS_IOS)
   DIR_LOCALES,  // Directory where locale resources are stored.
+#endif
 
   // Valid only in development environment; TODO(darin): move this
   UI_DIR_TEST_DATA,  // Directory where unit test data resides.