doc.write blocking intervention warning header

third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp

Index: third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
diff --git a/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp b/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
index aab6e32f909db869ae8dbc90db1b6bae95c83f27..3cc8bffe762f6cb9b81875a51faf3b385f513fe9 100644
--- a/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
+++ b/third_party/WebKit/Source/core/fetch/ResourceFetcher.cpp
@@ -624,14 +624,19 @@ void ResourceFetcher::initializeResourceRequest(
     ResourceRequest& request,
     Resource::Type type,
     FetchRequest::DeferOption defer) {
-  if (request.getCachePolicy() == WebCachePolicy::UseProtocolCachePolicy)
-    request.setCachePolicy(
-        context().resourceRequestCachePolicy(request, type, defer));
+  std::pair<AtomicString, AtomicString> customHeader;
+  if (request.getCachePolicy() == WebCachePolicy::UseProtocolCachePolicy) {
+    request.setCachePolicy(context().resourceRequestCachePolicy(
+        request, type, defer, customHeader));
+  }
   if (request.requestContext() == WebURLRequest::RequestContextUnspecified)
     determineRequestContext(request, type);
   if (type == Resource::LinkPrefetch)
     request.setHTTPHeaderField(HTTPNames::Purpose, "prefetch");
 
+  if (!customHeader.first.isEmpty())
+    request.setHTTPHeaderField(customHeader.first, customHeader.second);
+
   context().addAdditionalRequestHeaders(
       request,
       (type == Resource::MainResource) ? FetchMainResource : FetchSubresource);