Block subresource requests whose URLs include credentials.

third_party/WebKit/Source/core/loader/FrameFetchContext.cpp

Index: third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
diff --git a/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp b/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
index d267da610300fd28151cce77f7237c92549ea124..35b4d0f1f9ba3167a5d6ff69dd70de23f6f5de7e 100644
--- a/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
+++ b/third_party/WebKit/Source/core/loader/FrameFetchContext.cpp
@@ -803,6 +803,10 @@ ResourceRequestBlockedReason FrameFetchContext::canRequestInternal(
       Deprecation::countDeprecation(
           frame()->document(),
           UseCounter::RequestedSubresourceWithEmbeddedCredentials);
+      // TODO(mkwst): Remove the runtime-enabled check in M59:
+      // https://www.chromestatus.com/feature/5669008342777856
+      if (RuntimeEnabledFeatures::blockCredentialedSubresourcesEnabled())
+        return ResourceRequestBlockedReason::Origin;
     }
   }