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 11a211fa7b2dece612a28152f7a3705e1f34be08..d2ece160c998c05ae90b3d44c7cd10192ed2e3a7 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"
@@ -80,6 +81,7 @@ bool ChromeNetworkDelegate::g_never_throttle_requests_ = false;
 namespace {
 
 const char kDNTHeader[] = "DNT";
+const char kClientHintsDevicePixelRatioHeader[] = "CH-DPR";

[mmenke, 2013/09/25 16:26:19]

optional:  This may make more sense as a static member of the client hints
class.

[mmenke, 2013/09/25 16:26:19]

ERm...This seems to violate the spec linked in the other file.  You're adding
CH-DPR: 1.0.

Shouldn't it be CH: DPR=1.0?  Or is there a newer spec?

[bengr, 2013/09/25 17:25:52]

There's a newer spec. The CL points to it but a comment in the code pointed to
the old one. I've updated the comment.

[bengr, 2013/09/25 17:25:52]

Done.

 
 // If the |request| failed due to problems with a proxy, forward the error to
 // the proxy extension API.
@@ -334,6 +336,11 @@ 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 +425,11 @@ int ChromeNetworkDelegate::OnBeforeURLRequest(
   if (enable_do_not_track_ && enable_do_not_track_->GetValue())
     request->SetExtraRequestHeaderByName(kDNTHeader, "1", true /* override */);
 
+  if (client_hints_) {
+    request->SetExtraRequestHeaderByName(kClientHintsDevicePixelRatioHeader,
+                                         client_hints_->GetString(), true);
+  }
+
   bool force_safe_search = force_google_safe_search_ &&
                            force_google_safe_search_->GetValue();