media: Send chrome-cache: frfr on first request.

media/blink/resource_multibuffer_data_provider.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/blink/resource_multibuffer_data_provider.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 67 matching lines @@
         FROM_HERE, base::Bind(&ResourceMultiBufferDataProvider::Terminate,
                               weak_factory_.GetWeakPtr()));
     return;
   }
 
   request.SetHTTPHeaderField(
       WebString::FromUTF8(net::HttpRequestHeaders::kRange),
       WebString::FromUTF8(
           net::HttpByteRange::RightUnbounded(byte_pos()).GetHeaderValue()));
 
+  if (url_data_->length() == kPositionNotSpecified &&
+      url_data_->CachedSize() == 0 && url_data_->BytesReadFromCache() == 0) {
+    // This lets flywheel know that we don't have anything previously cached
+    // data for this resource. We can only send it if this is the first request
+    // for this resource.
+    request.SetHTTPHeaderField(WebString::FromUTF8("chrome-proxy"),

[bengr, 2017/04/27 22:10:18]

You are unconditionally adding a header that we conditionally send only to the
data reduction proxy. Doing this will cause VerifyHttpRequestHeaders in
data_reduction_proxy_network_delegate.cc
(https://codesearch.chromium.org/chromium/src/components/data_reduction_proxy/...)
to fail a DCHECK that this header isn't present when the request is not proxied.

Since blink code doesn't know what proxy connection will be used, your best bet
is to add it here as you did and remove it in DRP-specific network code.

The DRP network code calls VerifyHttpRequestHeaders in three places in that
delegate file. Your best bet is to remove 'C-P: frfr' just before those calls if
the d-r-p is not being used. 

[tombergan, 2017/04/27 23:02:52]

Why does the following code not run into the same error?
https://cs.chromium.org/chromium/src/chrome/browser/renderer_context_menu/ren...

[hubbe, 2017/04/27 23:16:26]

Uses different headers..

[hubbe, 2017/04/27 23:21:32]

Or maybe because it dumps two headers into one field?

+                               WebString::FromUTF8("frfr"));
+  }
+
   // We would like to send an if-match header with the request to
   // tell the remote server that we really can't handle files other
   // than the one we already started playing. Unfortunately, doing
   // so will disable the http cache, and possibly other proxies
   // along the way. See crbug/504194 and crbug/689989 for more information.
 
   url_data_->frame()->SetReferrerForRequest(request, blink::WebURL());
 
   // Disable compression, compression for audio/video doesn't make sense...
   request.SetHTTPHeaderField(
@@ skipping 452 matching lines @@
   }
 
   if (byte_pos() != first_byte_position) {
     return false;
   }
 
   return true;
 }
 
 }  // namespace media