Transmit a X-Chrome-UMA-Enabled bit to Google domains from clients that have UMA enabled.

chrome/browser/net/chrome_network_delegate.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/net/chrome_network_delegate.h"
 
 #include "base/logging.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/content_settings/cookie_settings.h"
 #include "chrome/browser/content_settings/tab_specific_content_settings.h"
 #include "chrome/browser/custom_handlers/protocol_handler_registry.h"
 #include "chrome/browser/extensions/api/proxy/proxy_api.h"
 #include "chrome/browser/extensions/api/web_request/web_request_api.h"
 #include "chrome/browser/extensions/extension_event_router_forwarder.h"
 #include "chrome/browser/extensions/extension_info_map.h"
 #include "chrome/browser/extensions/extension_process_manager.h"
+#include "chrome/browser/google/google_util.h"
+#include "chrome/browser/metrics/metrics_service.h"
 #include "chrome/browser/prefs/pref_member.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/task_manager/task_manager.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/resource_request_info.h"
 #include "net/base/host_port_pair.h"
 #include "net/base/net_errors.h"
 #include "net/base/net_log.h"
@@ skipping 69 matching lines @@
     return;
 
   int process_id, render_view_id;
   if (info->GetAssociatedRenderView(&process_id, &render_view_id)) {
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
         base::Bind(&NotifyEPMRequestStatus,
                    status, profile_id, process_id, render_view_id));
   }
 }
 
+// Prepare a PrefMember for ChromeNetworkDelegate's use by initializing it with
+// a desired pref and moving it to the IO thread.
+void InitializePrefMember(BooleanPrefMember* pref_member,
+                          PrefService* pref_service,
+                          const char* pref_name) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  pref_member->Init(pref_name, pref_service, NULL);
+  pref_member->MoveToThread(BrowserThread::IO);
+}
+
 }  // namespace
 
 ChromeNetworkDelegate::ChromeNetworkDelegate(
     ExtensionEventRouterForwarder* event_router,
     ExtensionInfoMap* extension_info_map,
     const policy::URLBlacklistManager* url_blacklist_manager,
     void* profile,
     CookieSettings* cookie_settings,
-    BooleanPrefMember* enable_referrers)
+    BrowserVisibility visibility,
+    BooleanPrefMember* enable_referrers,
+    BooleanPrefMember* enable_metrics)
     : event_router_(event_router),
       profile_(profile),
       cookie_settings_(cookie_settings),
+      visibility_(visibility),
       extension_info_map_(extension_info_map),
       enable_referrers_(enable_referrers),
+      enable_metrics_(enable_metrics),
       url_blacklist_manager_(url_blacklist_manager) {
   DCHECK(event_router);
   DCHECK(enable_referrers);
   DCHECK(!profile || cookie_settings);
 }
 
 ChromeNetworkDelegate::~ChromeNetworkDelegate() {}
 
 // static
 void ChromeNetworkDelegate::InitializeReferrersEnabled(
     BooleanPrefMember* enable_referrers,
     PrefService* pref_service) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  enable_referrers->Init(prefs::kEnableReferrers, pref_service, NULL);
-  enable_referrers->MoveToThread(BrowserThread::IO);
+  InitializePrefMember(enable_referrers, pref_service, prefs::kEnableReferrers);
+}
+
+// static
+void ChromeNetworkDelegate::InitializeMetricsEnabled(
+    BooleanPrefMember* enable_metrics,
+    PrefService* pref_service) {
+  InitializePrefMember(enable_metrics, pref_service,
+                       prefs::kMetricsReportingEnabled);
 }
 
 int ChromeNetworkDelegate::OnBeforeURLRequest(
     net::URLRequest* request,
     const net::CompletionCallback& callback,
     GURL* new_url) {
 #if defined(ENABLE_CONFIGURATION_POLICY)
   // TODO(joaodasilva): This prevents extensions from seeing URLs that are
   // blocked. However, an extension might redirect the request to another URL,
   // which is not blocked.
@@ skipping 13 matching lines @@
   if (!enable_referrers_->GetValue())
     request->set_referrer(std::string());
   return ExtensionWebRequestEventRouter::GetInstance()->OnBeforeRequest(
       profile_, extension_info_map_.get(), request, callback, new_url);
 }
 
 int ChromeNetworkDelegate::OnBeforeSendHeaders(
     net::URLRequest* request,
     const net::CompletionCallback& callback,
     net::HttpRequestHeaders* headers) {
+  // Attach any applicable Chrome metrics headers. This is a best-effort attempt
+  // where failure will not cause OnBeforeSendHeaders to back out.
+  AddChromeMetricsStateHeader(request, headers);
+
   return ExtensionWebRequestEventRouter::GetInstance()->OnBeforeSendHeaders(
       profile_, extension_info_map_.get(), request, callback, headers);
 }
 
 void ChromeNetworkDelegate::OnSendHeaders(
     net::URLRequest* request,
     const net::HttpRequestHeaders& headers) {
   ExtensionWebRequestEventRouter::GetInstance()->OnSendHeaders(
       profile_, extension_info_map_.get(), request, headers);
 }
@@ skipping 119 matching lines @@
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
         base::Bind(&TabSpecificContentSettings::CookieChanged,
                    render_process_id, render_view_id,
                    request->url(), request->first_party_for_cookies(),
                    cookie_line, *options, !allow));
   }
 
   return allow;
 }
+
+void ChromeNetworkDelegate::AddChromeMetricsStateHeader(
+    net::URLRequest* request,
+    net::HttpRequestHeaders* headers) {
+  // Note our criteria for attaching Chrome experiment headers:
+  // 1. We only transmit to *.google.<TLD> domains. NOTE that this use of
+  //    google_util helpers to check this does not guarantee that the URL is
+  //    Google-owned, only that it is of the form *.google.<TLD>. In the future
+  //    we may choose to reinforce this check.
+  // 2. We must verify that we are transmitting for a profile network context
+  //    and not the system context. We do this by checking |profile_|, as it is
+  //    NULL when we're in the system context.
+  // 3. We only transmit for non-Incognito profiles. Ensure that the pref has
+  //    been passed in and is true.
+  // 4. For the X-Chrome-UMA-Enabled bit, we only set it if UMA is in fact
+  //    enabled for this install of Chrome.
+  if (google_util::IsGoogleDomainUrl(request->url().spec(),
+                                     google_util::ALLOW_SUBDOMAIN) &&
+      profile_ && visibility_ == NORMAL && enable_metrics_ &&
+      enable_metrics_->GetValue()) {
+    headers->SetHeader("X-Chrome-UMA-Enabled", "1");
+  }
+}