Add LOG(ERROR) to ClientConfig override parsing

Allows a non-Chromium dev to notice when a bad ClientConfig has been
given. Only does LOG(ERROR) in non-debug builds though since DCHECK is
otherwise sufficent.

Bug: 724242
Change-Id: Id3b7138e81329c296e0aaeac326e2e212e4362e6
Reviewed-on: https://chromium-review.googlesource.com/1087513Reviewed-by: Ryan Sturm <ryansturm@chromium.org>
Commit-Queue: Robert Ogden <robertogden@chromium.org>
Cr-Commit-Position: refs/heads/master@{#564755}

components/data_reduction_proxy/core/browser/data_reduction_proxy_config_service_client.cc

@@ -256,11 +256,12 @@ void DataReductionProxyConfigServiceClient::RetrieveConfig() {
     std::string override_config;
     bool b64_decode_ok =
         base::Base64Decode(client_config_override_, &override_config);
-    DCHECK(b64_decode_ok) << "The given ClientConfig is not valid base64";
+    LOG_IF(DFATAL, !b64_decode_ok)
+        << "The given ClientConfig is not valid base64";
 
     ClientConfig config;
     bool was_valid_config = config.ParseFromString(override_config);
-    DCHECK(was_valid_config) << "The given ClientConfig was invalid.";
+    LOG_IF(DFATAL, !was_valid_config) << "The given ClientConfig was invalid.";
     if (was_valid_config)
       ParseAndApplyProxyConfig(config);
     return;