media: Stop sending if-match headers for media fetch requests.

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_->etag().empty()) {
-    request.setHTTPHeaderField(WebString::fromUTF8("If-Match"),
-                               WebString::fromUTF8(url_data_->etag()));
-  }
+  // 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(
       WebString::fromUTF8(net::HttpRequestHeaders::kAcceptEncoding),
       WebString::fromUTF8("identity;q=1, *;q=0"));
 
   // Check for our test WebAssociatedURLLoader.
   std::unique_ptr<WebAssociatedURLLoader> loader;
@@ skipping 444 matching lines @@
   }
 
   if (byte_pos() != first_byte_position) {
     return false;
   }
 
   return true;
 }
 
 }  // namespace media