Do not issue preflight for crossorigin media resource loads.

content/renderer/media/buffered_resource_loader.cc

Index: content/renderer/media/buffered_resource_loader.cc
diff --git a/content/renderer/media/buffered_resource_loader.cc b/content/renderer/media/buffered_resource_loader.cc
index 278d5bacde17ef9d695259433b3a18fb16788132..5429c3268e1ed64bf2417d28617dcf082d5fb669 100644
--- a/content/renderer/media/buffered_resource_loader.cc
+++ b/content/renderer/media/buffered_resource_loader.cc
@@ -188,6 +188,8 @@ void BufferedResourceLoader::Start(
           WebURLLoaderOptions::CrossOriginRequestPolicyAllow;
     } else {
       options.exposeAllResponseHeaders = true;
+      // The author header set is empty, no preflight should go ahead.
+      options.preflightPolicy = WebURLLoaderOptions::PreventPreflight;
       options.crossOriginRequestPolicy =
           WebURLLoaderOptions::CrossOriginRequestPolicyUseAccessControl;
       if (cors_mode_ == kUseCredentials)