Removes the --no-referrers command line switch

This is one of a series of three CLs adding more uniformity
to referrer controls' implementation. The switch's functionality
remains accessible via disabling the enable_referrers pref.

The changes in this CL comprise:
1. Removing the switch
2. Removing the previous calls directly checking the switch, rather than
the enable_referrers pref. Happily, these checks of the switch were both
redundant with the later check of enable_referrers performed in
NetworkDelegate::NotifyBeforeURLRequest.
3. A nominal amount of refactoring of some dead/nearly-dead referrer-related
code:
  - network::ComputeReferrer removed from loader_util.cc (after removing
the --no-referrers switch, this method now duplicates GURL::GetAsReferrer).
  - content::Referrer::SetReferrerForRequest removed (it had no callers).

R=gab, falken

Bug: 1004486
Change-Id: I00bc503d0954700565047a188bbb9842c4d4bc9e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1808144
Commit-Queue: David Van Cleve <davidvc@chromium.org>
Reviewed-by: Gabriel Charette <gab@chromium.org>
Reviewed-by: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699403}

chrome/browser/prefs/chrome_command_line_pref_store.cc

@@ -67,7 +67,6 @@ const CommandLinePrefStore::BooleanSwitchToPreferenceMapEntry
          true},
         {switches::kAllowOutdatedPlugins, prefs::kPluginsAllowOutdated, true},
         {switches::kNoPings, prefs::kEnableHyperlinkAuditing, false},
-        {network::switches::kNoReferrers, prefs::kEnableReferrers, false},
         {switches::kAllowRunningInsecureContent,
          prefs::kWebKitAllowRunningInsecureContent, true},
         {switches::kAllowCrossOriginAuthPrompt,

content/browser/renderer_host/render_process_host_impl.cc

@@ -2927,7 +2927,6 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
   // Propagate the following switches to the renderer command line (along
   // with any associated values) if present in the browser command line.
   static const char* const kSwitchNames[] = {
-    network::switches::kNoReferrers,
     network::switches::kExplicitlyAllowedPorts,
     service_manager::switches::kDisableInProcessStackTraces,
     service_manager::switches::kDisableSeccompFilterSandbox,

content/browser/utility_process_host.cc

@@ -392,7 +392,6 @@ bool UtilityProcessHost::StartProcess() {
       network::switches::kIgnoreUrlFetcherCertRequests,
       network::switches::kLogNetLog,
       network::switches::kNetLogCaptureMode,
-      network::switches::kNoReferrers,
       network::switches::kExplicitlyAllowedPorts,
       service_manager::switches::kNoSandbox,
 #if defined(OS_MACOSX)

content/common/service_worker/service_worker_loader_helpers.cc

@@ -130,7 +130,7 @@ ServiceWorkerLoaderHelpers::ComputeRedirectInfo(
       original_request.method, original_request.url,
       original_request.site_for_cookies, first_party_url_policy,
       original_request.referrer_policy,
-      network::ComputeReferrer(original_request.referrer),
+      original_request.referrer.GetAsReferrer().spec(),
       response_head.headers->response_code(),
       original_request.url.Resolve(new_location),
       net::RedirectUtil::GetReferrerPolicyHeader(response_head.headers.get()),

content/public/common/referrer.cc

@@ -116,13 +116,6 @@ url::Origin Referrer::SanitizeOriginForRequest(
   return url::Origin::Create(sanitizied_referrer.url);
 }
 
-// static
-void Referrer::SetReferrerForRequest(net::URLRequest* request,
-                                     const Referrer& referrer) {
-  request->SetReferrer(network::ComputeReferrer(referrer.url));
-  request->set_referrer_policy(ReferrerPolicyForUrlRequest(referrer.policy));
-}
-
 // static
 net::URLRequest::ReferrerPolicy Referrer::ReferrerPolicyForUrlRequest(
     network::mojom::ReferrerPolicy referrer_policy) {

content/public/common/referrer.h

@@ -47,9 +47,6 @@ struct CONTENT_EXPORT Referrer {
       const url::Origin& initiator,
       network::mojom::ReferrerPolicy policy);
 
-  static void SetReferrerForRequest(net::URLRequest* request,
-                                    const Referrer& referrer);
-
   static net::URLRequest::ReferrerPolicy ReferrerPolicyForUrlRequest(
       network::mojom::ReferrerPolicy referrer_policy);
 

services/network/loader_util.cc

@@ -124,15 +124,6 @@ scoped_refptr<HttpRawRequestResponseInfo> BuildRawRequestResponseInfo(
   return info;
 }
 
-std::string ComputeReferrer(const GURL& referrer) {
-  if (!referrer.is_valid() || base::CommandLine::ForCurrentProcess()->HasSwitch(
-                                  switches::kNoReferrers)) {
-    return std::string();
-  }
-
-  return referrer.spec();
-}
-
 void LogConcerningRequestHeaders(const net::HttpRequestHeaders& request_headers,
                                  bool added_during_redirect) {
   net::HttpRequestHeaders::Iterator it(request_headers);

services/network/public/cpp/network_switches.cc

@@ -56,9 +56,6 @@ const char kNetLogCaptureMode[] = "net-log-capture-mode";
 // for the format.
 const char kSSLKeyLogFile[] = "ssl-key-log-file";
 
-// Don't send HTTP-Referer headers.
-const char kNoReferrers[] = "no-referrers";
-
 // Allows overriding the list of restricted ports by passing a comma-separated
 // list of port numbers.
 const char kExplicitlyAllowedPorts[] = "explicitly-allowed-ports";

services/network/public/cpp/network_switches.h

@@ -20,7 +20,6 @@ COMPONENT_EXPORT(NETWORK_CPP) extern const char kIgnoreUrlFetcherCertRequests[];
 COMPONENT_EXPORT(NETWORK_CPP) extern const char kLogNetLog[];
 COMPONENT_EXPORT(NETWORK_CPP) extern const char kNetLogCaptureMode[];
 COMPONENT_EXPORT(NETWORK_CPP) extern const char kSSLKeyLogFile[];
-COMPONENT_EXPORT(NETWORK_CPP) extern const char kNoReferrers[];
 COMPONENT_EXPORT(NETWORK_CPP) extern const char kExplicitlyAllowedPorts[];
 COMPONENT_EXPORT(NETWORK_CPP)
 extern const char kUnsafelyTreatInsecureOriginAsSecure[];

services/network/url_loader.cc

@@ -398,7 +398,7 @@ URLLoader::URLLoader(
   url_request_->set_method(request.method);
   url_request_->set_site_for_cookies(request.site_for_cookies);
   url_request_->set_attach_same_site_cookies(request.attach_same_site_cookies);
-  url_request_->SetReferrer(ComputeReferrer(request.referrer));
+  url_request_->SetReferrer(request.referrer.GetAsReferrer().spec());
   url_request_->set_referrer_policy(request.referrer_policy);
   url_request_->set_upgrade_if_insecure(request.upgrade_if_insecure);