Use via header to detect if cached main frame response is served by DRP

DRP does not set chrome-proxy response header for streamed responses. So
to detect an cached response is served by DRP, via header should be used
in addition to chrome-proxy header. This records more DRP PageLoadMetrics
metrics and sends more DRP pingbacks.

Change-Id: I13f9fcda455aae53cab19a6fe1d9d5421903aca8

Bug: 924211
Change-Id: I13f9fcda455aae53cab19a6fe1d9d5421903aca8
Reviewed-on: https://chromium-review.googlesource.com/c/1426521Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Commit-Queue: rajendrant <rajendrant@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624958}

chrome/browser/data_reduction_proxy/data_reduction_proxy_chrome_settings.cc

@@ -297,7 +297,11 @@ DataReductionProxyChromeSettings::CreateDataFromNavigationHandle(
     return data;
 
   if (handle->WasResponseCached() &&
-      headers->HasHeader(data_reduction_proxy::chrome_proxy_header()) &&
+      (headers->HasHeader(data_reduction_proxy::chrome_proxy_header()) ||
+       // Check for via header since Chrome-Proxy header maybe missing in
+       // streamed responses.
+       data_reduction_proxy::HasDataReductionProxyViaHeader(*headers,
+                                                            nullptr)) &&
       !handle->GetURL().SchemeIsCryptographic()) {
     data->set_was_cached_data_reduction_proxy_response(true);
   }

chrome/browser/data_reduction_proxy/data_reduction_proxy_chrome_settings_unittest.cc

@@ -443,6 +443,23 @@ TEST_F(DataReductionProxyChromeSettingsTest, CreateHTTPSDataCachedResponse) {
   EXPECT_FALSE(data->was_cached_data_reduction_proxy_response());
 }
 
+TEST_F(DataReductionProxyChromeSettingsTest,
+       CreateCachedResponseWithViaHeader) {
+  std::string raw_headers =
+      "HTTP/1.0 200 OK\n"
+      "via: 1.1 Chrome-Compression-Proxy\n";
+  content::MockNavigationHandle handle(GURL(kUrl), main_rfh());
+  scoped_refptr<net::HttpResponseHeaders> headers =
+      new net::HttpResponseHeaders(net::HttpUtil::AssembleRawHeaders(
+          raw_headers.c_str(), raw_headers.size()));
+  handle.set_response_headers(headers.get());
+  handle.set_was_response_cached(true);
+  auto data = drp_chrome_settings_->CreateDataFromNavigationHandle(
+      &handle, headers.get());
+
+  EXPECT_TRUE(data->was_cached_data_reduction_proxy_response());
+}
+
 TEST_F(DataReductionProxyChromeSettingsTest, CreateDataWithLitePage) {
   std::string raw_headers =
       "HTTP/1.0 200 OK\n"

components/data_reduction_proxy/core/browser/data_reduction_proxy_network_delegate.cc

@@ -511,7 +511,11 @@ void DataReductionProxyNetworkDelegate::OnHeadersReceivedInternal(
 
   if (request->was_cached() && request->url().SchemeIsHTTPOrHTTPS() &&
       !request->url().SchemeIsCryptographic() &&
-      original_response_headers->HasHeader(chrome_proxy_header())) {
+      (original_response_headers->HasHeader(chrome_proxy_header()) ||
+       // Check for via header since Chrome-Proxy header maybe missing in
+       // streamed responses.
+       data_reduction_proxy::HasDataReductionProxyViaHeader(
+           *original_response_headers, nullptr))) {
     DataReductionProxyData* data =
         DataReductionProxyData::GetDataAndCreateIfNecessary(request);
     data->set_was_cached_data_reduction_proxy_response(true);