Add Category wrapper for ContentSuggestions on iOS

ios/chrome/browser/content_suggestions/BUILD.gn

Index: ios/chrome/browser/content_suggestions/BUILD.gn
diff --git a/ios/chrome/browser/content_suggestions/BUILD.gn b/ios/chrome/browser/content_suggestions/BUILD.gn
index ce76fb1c51cebf9735860aec54c5e9708e4db208..6036ee6b1ecbaeb6814610e5a6bb680c14257a53 100644
--- a/ios/chrome/browser/content_suggestions/BUILD.gn
+++ b/ios/chrome/browser/content_suggestions/BUILD.gn
@@ -5,6 +5,8 @@
 source_set("content_suggestions") {
   configs += [ "//build/config/compiler:enable_arc" ]
   sources = [
+    "content_suggestions_category_wrapper.h",
+    "content_suggestions_category_wrapper.mm",
     "content_suggestions_coordinator.h",
     "content_suggestions_coordinator.mm",
     "content_suggestions_mediator.h",
@@ -22,3 +24,16 @@ source_set("content_suggestions") {
     "//ui/base",
   ]
 }
+
+source_set("unit_tests") {
+  testonly = true
+  sources = [
+    "content_suggestions_category_wrapper_unittest.mm",
+  ]
+  deps = [
+    ":content_suggestions",
+    "//components/ntp_snippets",
+    "//testing/gtest",
+  ]
+  configs += [ "//build/config/compiler:enable_arc" ]
+}