Client Hints

chrome/browser/net/chrome_network_delegate.cc

Index: chrome/browser/net/chrome_network_delegate.cc
diff --git a/chrome/browser/net/chrome_network_delegate.cc b/chrome/browser/net/chrome_network_delegate.cc
index 4de27d4fd55fa7fbde1af8979694dd0018b3389f..230b40b3fcfd613ffa05ba5603efa781be3e0df1 100644
--- a/chrome/browser/net/chrome_network_delegate.cc
+++ b/chrome/browser/net/chrome_network_delegate.cc
@@ -30,6 +30,7 @@
 #include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/google/google_util.h"
 #include "chrome/browser/net/chrome_network_data_saving_metrics.h"
+#include "chrome/browser/net/client_hints.h"
 #include "chrome/browser/net/connect_interceptor.h"
 #include "chrome/browser/net/load_time_stats.h"
 #include "chrome/browser/performance_monitor/performance_monitor.h"
@@ -334,6 +335,11 @@ void ChromeNetworkDelegate::set_predictor(
       new chrome_browser_net::ConnectInterceptor(predictor));
 }
 
+void ChromeNetworkDelegate::SetEnableClientHints() {
+  client_hints_.reset(new ClientHints());
+  client_hints_->Init();
+}
+
 // static
 void ChromeNetworkDelegate::NeverThrottleRequests() {
   g_never_throttle_requests_ = true;
@@ -418,6 +424,12 @@ int ChromeNetworkDelegate::OnBeforeURLRequest(
   if (enable_do_not_track_ && enable_do_not_track_->GetValue())
     request->SetExtraRequestHeaderByName(kDNTHeader, "1", true /* override */);
 
+  if (client_hints_) {
+    request->SetExtraRequestHeaderByName(
+        ClientHints::kDevicePixelRatioHeader,
+        client_hints_->GetDevicePixelRatioHeader(), true);
+  }
+
   bool force_safe_search = force_google_safe_search_ &&
                            force_google_safe_search_->GetValue();