Stop passing raw pointers to base::Value API in c/b/chromeos and c/b/extensions

chrome/browser/extensions/api/proxy/proxy_api_helpers.cc

Index: chrome/browser/extensions/api/proxy/proxy_api_helpers.cc
diff --git a/chrome/browser/extensions/api/proxy/proxy_api_helpers.cc b/chrome/browser/extensions/api/proxy/proxy_api_helpers.cc
index f14448593a28c467368309ab82250feb66a477b0..48b590a2516875df99c0b7f9bdfd4a487fac1716 100644
--- a/chrome/browser/extensions/api/proxy/proxy_api_helpers.cc
+++ b/chrome/browser/extensions/api/proxy/proxy_api_helpers.cc
@@ -330,12 +330,12 @@ std::unique_ptr<base::DictionaryValue> CreateProxyConfigDict(
       } else if (!pac_data.empty()) {
         if (!CreateDataURLFromPACScript(pac_data, &url)) {
           *error = "Internal error, at base64 encoding of 'pacScript.data'.";
-          return NULL;
+          return nullptr;
         }
       } else {
         *error = "Proxy mode 'pac_script' requires a 'pacScript' field with "
                  "either a 'url' field or a 'data' field.";
-        return NULL;
+        return nullptr;
       }
       result_proxy_config =
           ProxyConfigDictionary::CreatePacScript(url, pac_mandatory);
@@ -344,7 +344,7 @@ std::unique_ptr<base::DictionaryValue> CreateProxyConfigDict(
     case ProxyPrefs::MODE_FIXED_SERVERS: {
       if (proxy_rules_string.empty()) {
         *error = "Proxy mode 'fixed_servers' requires a 'rules' field.";
-        return NULL;
+        return nullptr;
       }
       result_proxy_config = ProxyConfigDictionary::CreateFixedServers(
           proxy_rules_string, bypass_list);