Exclude simple headers when building Access-Control-Request-Headers

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

Index: third_party/WebKit/Source/core/fetch/CrossOriginAccessControl.cpp
diff --git a/third_party/WebKit/Source/core/fetch/CrossOriginAccessControl.cpp b/third_party/WebKit/Source/core/fetch/CrossOriginAccessControl.cpp
index 7d3f7a5fbd2fc6416da0afdd35ab4324368f4975..8b794e834a16bb03b8310aec1f672aa14fd56640 100644
--- a/third_party/WebKit/Source/core/fetch/CrossOriginAccessControl.cpp
+++ b/third_party/WebKit/Source/core/fetch/CrossOriginAccessControl.cpp
@@ -26,6 +26,7 @@
 
 #include "core/fetch/CrossOriginAccessControl.h"
 
+#include "core/fetch/FetchUtils.h"
 #include "core/fetch/Resource.h"
 #include "core/fetch/ResourceLoaderOptions.h"
 #include "platform/network/HTTPParsers.h"
@@ -83,26 +84,23 @@ ResourceRequest createAccessControlPreflightRequest(const ResourceRequest& reque
     const HTTPHeaderMap& requestHeaderFields = request.httpHeaderFields();
 
     if (requestHeaderFields.size() > 0) {
-        // Sort header names lexicographically: https://crbug.com/452391
         // Fetch API Spec:
         //   https://fetch.spec.whatwg.org/#cors-preflight-fetch-0
         Vector<String> headers;
         for (const auto& header : requestHeaderFields) {
+            if (FetchUtils::isSimpleHeader(header.key, header.value)) {
+                // Exclude simple headers.
+                continue;
+            }
             if (equalIgnoringCase(header.key, "referer")) {
                 // When the request is from a Worker, referrer header was added
                 // by WorkerThreadableLoader. But it should not be added to
                 // Access-Control-Request-Headers header.
                 continue;
             }
-            if (equalIgnoringCase(header.key, "save-data")) {
-                // As a short-term fix, exclude Save-Data from
-                // Access-Control-Request-Headers header.
-                // TODO(rajendrant): crbug.com/601092 Longer-term all simple
-                // headers should be excluded as well.
-                continue;
-            }
             headers.append(header.key.lower());
         }
+        // Sort header names lexicographically.
         std::sort(headers.begin(), headers.end(), WTF::codePointCompareLessThan);
         StringBuilder headerBuffer;
         for (const String& header : headers) {