Remove outdated comment about CSP for <track>

Source/core/fetch/ResourceFetcher.cpp

Index: Source/core/fetch/ResourceFetcher.cpp
diff --git a/Source/core/fetch/ResourceFetcher.cpp b/Source/core/fetch/ResourceFetcher.cpp
index d647c8d06b6d1c1a1c99a7d3dd93af511429500a..8dc8513defef24d0d1ca40d95d3dd68eaeb0343b 100644
--- a/Source/core/fetch/ResourceFetcher.cpp
+++ b/Source/core/fetch/ResourceFetcher.cpp
@@ -507,8 +507,6 @@ bool ResourceFetcher::canRequest(Resource::Type type, const KURL& url, const Res
     case Resource::LinkSubresource:
         break;
     case Resource::TextTrack:
-        // Cues aren't called out in the CSP spec yet, but they only work with a media element
-        // so use the media policy.
         if (!shouldBypassMainWorldContentSecurityPolicy && !m_document->contentSecurityPolicy()->allowMediaFromSource(url))
             return false;
         break;