Use application locale for accept headers in Incognito

Bug: 1077547
Change-Id: I36a18d846e75fd89237e28b777910d88a346e354
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2208545
Commit-Queue: Megan Jablonski <megjablon@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Reviewed-by: Ramin Halavati <rhalavati@chromium.org>
Cr-Commit-Position: refs/heads/master@{#771149}

chrome/browser/net/network_context_configuration_browsertest.cc

@@ -1386,17 +1386,26 @@ IN_PROC_BROWSER_TEST_P(NetworkContextConfigurationBrowserTest,
   FlushNetworkInterface();
   std::string accept_language2, user_agent2;
   ASSERT_TRUE(FetchHeaderEcho("accept-language", &accept_language2));
-  EXPECT_EQ(system ? kNoAcceptLanguage : "uk", accept_language2);
+  if (GetProfile()->IsOffTheRecord()) {
+    EXPECT_EQ(system ? kNoAcceptLanguage : "en-US,en;q=0.9", accept_language2);
+  } else {
+    EXPECT_EQ(system ? kNoAcceptLanguage : "uk", accept_language2);
+  }
   ASSERT_TRUE(FetchHeaderEcho("user-agent", &user_agent2));
   EXPECT_EQ(::GetUserAgent(), user_agent2);
 
   // Try a more complicated one, with multiple languages.
   browser()->profile()->GetPrefs()->SetString(language::prefs::kAcceptLanguages,
-                                              "uk, en_US");
+                                              "uk, en-US");
   FlushNetworkInterface();
   std::string accept_language3, user_agent3;
   ASSERT_TRUE(FetchHeaderEcho("accept-language", &accept_language3));
-  EXPECT_EQ(system ? kNoAcceptLanguage : "uk,en_US;q=0.9", accept_language3);
+  if (GetProfile()->IsOffTheRecord()) {
+    EXPECT_EQ(system ? kNoAcceptLanguage : "en-US,en;q=0.9", accept_language3);
+  } else {
+    EXPECT_EQ(system ? kNoAcceptLanguage : "uk,en-US;q=0.9,en;q=0.8",
+              accept_language3);
+  }
   ASSERT_TRUE(FetchHeaderEcho("user-agent", &user_agent3));
   EXPECT_EQ(::GetUserAgent(), user_agent3);
 }

chrome/browser/net/profile_network_context_service.cc

@@ -35,6 +35,7 @@
 #include "components/certificate_transparency/pref_names.h"
 #include "components/content_settings/core/browser/host_content_settings_map.h"
 #include "components/language/core/browser/pref_names.h"
+#include "components/language/core/common/locale_util.h"
 #include "components/metrics/metrics_pref_names.h"
 #include "components/pref_registry/pref_registry_syncable.h"
 #include "components/prefs/pref_registry_simple.h"
@@ -413,6 +414,10 @@ void ProfileNetworkContextService::OnThirdPartyCookieBlockingChanged(
 }
 
 std::string ProfileNetworkContextService::ComputeAcceptLanguage() const {
+  if (profile_->IsOffTheRecord()) {
+    return ComputeAcceptLanguageFromPref(
+        g_browser_process->GetApplicationLocale());
+  }
   return ComputeAcceptLanguageFromPref(pref_accept_language_.GetValue());
 }