Bug 1570159 - CreatePairwiseWhitelistURI return success when it cannot get host from the top-level page. r=Ehsan

Before this patch, when we cannot get the host name from the top-level page, for example,
aboout page, UrlClassifeirCommon::CreatePairwiseWhitelistURI returns an error.

After this patch, when |GetHost| fails, we returns NS_OK to just skip looking up
whiltelist for this URI. Note that the lookup against blacklist tables will
still be performed.

Differential Revision: https://phabricator.services.mozilla.com/D49983

--HG--
extra : moz-landing-system : lando

netwerk/url-classifier/AsyncUrlChannelClassifier.cpp

@@ -707,16 +707,22 @@ nsresult FeatureData::InitializeList(
   nsIUrlClassifierFeature::URIType URIType;
   nsresult rv = mFeature->GetURIByListType(aChannel, aListType, &URIType,
                                            getter_AddRefs(uri));
-  if (NS_WARN_IF(NS_FAILED(rv)) || !uri) {
+  if (NS_WARN_IF(NS_FAILED(rv))) {
     if (UC_LOG_ENABLED()) {
       nsAutoCString errorName;
       GetErrorName(rv, errorName);
-      UC_LOG(("FeatureData::InitializeList got an unexpected error (rv=%s)",
-              errorName.get()));
+      UC_LOG(("FeatureData::InitializeList[%p] got an unexpected error (rv=%s)",
+              this, errorName.get()));
     }
     return rv;
   }
 
+  if (!uri) {
+    // Return success when the URI is empty to conitnue to do the lookup.
+    UC_LOG(("FeatureData::InitializeList[%p] got an empty URL", this));
+    return NS_OK;
+  }
+
   nsCOMPtr<nsIURI> innermostURI = NS_GetInnermostURI(uri);
   if (NS_WARN_IF(!innermostURI)) {
     return NS_ERROR_FAILURE;

netwerk/url-classifier/UrlClassifierCommon.cpp

@@ -338,7 +338,17 @@ nsresult UrlClassifierCommon::CreatePairwiseWhiteListURI(nsIChannel* aChannel,
   // Craft a whitelist URL like "toplevel.page/?resource=third.party.domain"
   nsAutoCString pageHostname, resourceDomain;
   rv = topWinURI->GetHost(pageHostname);
-  NS_ENSURE_SUCCESS(rv, rv);
+  if (NS_FAILED(rv)) {
+    // When the top-level page doesn't support GetHost, for example, about:home,
+    // we don't return an error here; instead, we return success to make sure
+    // that the lookup process calling this API continues to run.
+    UC_LOG(
+        ("CreatePairwiseWhiteListURI: Cannot get host from the top-level "
+         "(channel=%p)",
+         aChannel));
+    return NS_OK;
+  }
+
   rv = chanPrincipal->GetBaseDomain(resourceDomain);
   NS_ENSURE_SUCCESS(rv, rv);
   nsAutoCString whitelistEntry = NS_LITERAL_CSTRING("http://") + pageHostname +