Support for new data reduction proxy via header

chrome/renderer/page_load_histograms.cc

 // Copyright (c) 2012 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 "chrome/renderer/page_load_histograms.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 14 matching lines @@
 #include "extensions/common/url_pattern.h"
 #include "net/base/url_util.h"
 #include "third_party/WebKit/public/platform/WebURLRequest.h"
 #include "third_party/WebKit/public/platform/WebURLResponse.h"
 #include "third_party/WebKit/public/web/WebDocument.h"
 #include "third_party/WebKit/public/web/WebFrame.h"
 #include "third_party/WebKit/public/web/WebPerformance.h"
 #include "third_party/WebKit/public/web/WebView.h"
 #include "url/gurl.h"
 
+#if defined(SPDY_PROXY_AUTH_ORIGIN)
+#include "net/http/http_response_headers.h"
+#endif
+
 using blink::WebDataSource;
 using blink::WebFrame;
 using blink::WebPerformance;
 using blink::WebString;
 using base::Time;
 using base::TimeDelta;
 using content::DocumentState;
 
 const size_t kPLTCount = 100;
 
@@ skipping 139 matching lines @@
   // not expected to contain any commas.
   // Example., Via: 1.0 Compression proxy, 1.1 Google promise preview
   base::SplitString(
       frame->dataSource()->response().httpHeaderField(kViaHeaderName).utf8(),
       ',', &values);
   return std::find(values.begin(), values.end(), via_value) != values.end();
 }
 
 // Returns true if the data reduction proxy was used. Note, this function will
 // produce a false positive if a page is fetched using SPDY and using a proxy,
-// and |kDatReductionProxyViaValue| is added to the Via header.
-// TODO(bengr): Plumb the hostname of the proxy from |HttpNetworkTransaction|
-// and check if it matches |SPDY_PROXY_AUTH_ORIGIN|.
+// and the data reduction proxy's via value is added to the Via header.
+// TODO(bengr): Plumb the hostname of the proxy and check if it matches
+// |SPDY_PROXY_AUTH_ORIGIN|.
 bool DataReductionProxyWasUsed(WebFrame* frame) {
 #if defined(SPDY_PROXY_AUTH_ORIGIN)
-  const char kDatReductionProxyViaValue[] = "1.1 Chrome Compression Proxy";
-  return ViaHeaderContains(frame, kDatReductionProxyViaValue);

[mef, 2014/02/12 21:36:50]

Given that ViaHeaderContains is still used in GetPreviewState maybe this module
should use that instead of hacking together HttpResponseHeaders?

[bengr, 2014/02/13 00:17:38]

ViaHeaderContains is only used by Promise as non-conforming to RFC 2616. I'd
prefer not to use it. Promise should fix their via header too.

+  DocumentState* document_state =
+      DocumentState::FromDataSource(frame->dataSource());
+  if (!document_state->was_fetched_via_proxy())
+    return false;
+
+  std::string via_header =
+      base::UTF16ToUTF8(frame->dataSource()->response().httpHeaderField("Via"));
+
+  if (via_header.empty())
+    return false;
+  std::string headers = "HTTP/1.1 200 OK\nVia: " + via_header + "\n\n";
+  std::replace(headers.begin(), headers.end(), '\n', '\0');

[mef, 2014/02/12 21:36:50]

Is it worth adding a comment that this produces a raw headers, expected by
HttpResponseHeaders constructor?

[bengr, 2014/02/13 00:17:38]

Done.

+  scoped_refptr<net::HttpResponseHeaders> response_headers(
+      new net::HttpResponseHeaders(headers));
+  return response_headers->IsChromeProxyResponse();
 #endif
   return false;
 }
 
 // Returns true if the provided URL is a referrer string that came from
 // a Google Web Search results page. This is a little non-deterministic
 // because desktop and mobile websearch differ and sometimes just provide
 // http://www.google.com/ as the referrer. In the case of /url we can be sure
 // that it came from websearch but we will be generous and allow for cases
 // where a non-Google URL was provided a bare Google URL as a referrer.
@@ skipping 817 matching lines @@
 
   DCHECK(document_state);
   DCHECK(ds);
   GURL url(ds->request().url());
   Time start = document_state->start_load_time();
   Time finish = document_state->finish_load_time();
   // TODO(mbelshe): should we log more stats?
   VLOG(1) << "PLT: " << (finish - start).InMilliseconds() << "ms "
           << url.spec();
 }