Move initialization of ChromeURLRequestContexts to the IO thread.

chrome/browser/net/chrome_url_request_context.cc

Index: chrome/browser/net/chrome_url_request_context.cc
===================================================================
--- chrome/browser/net/chrome_url_request_context.cc	(revision 29872)
+++ chrome/browser/net/chrome_url_request_context.cc	(working copy)
@@ -24,10 +24,31 @@
 #include "net/http/http_cache.h"
 #include "net/http/http_network_layer.h"
 #include "net/http/http_util.h"
+#include "net/proxy/proxy_config_service_fixed.h"
 #include "net/proxy/proxy_service.h"
 #include "net/url_request/url_request.h"
 #include "webkit/glue/webkit_glue.h"
 
+#if defined(OS_LINUX)
+#include "net/ocsp/nss_ocsp.h"
+#endif
+
+// TODO(eroman): Fix the definition ordering to match-up with the declaration
+//               ordering (this was done to help keep the diffs simple during
+//               refactor).
+
+// TODO(eroman): The ChromeURLRequestContext's Blacklist* is shared with the
+//               Profile... This is a problem since the Profile dies before
+//               the IO thread, so we may end up accessing a deleted variable.
+
+static void CheckCurrentlyOnIOThread() {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::IO));
+}
+
+static void CheckCurrentlyOnMainThread() {
+  DCHECK(ChromeThread::CurrentlyOn(ChromeThread::UI));
+}
+
 net::ProxyConfig* CreateProxyConfig(const CommandLine& command_line) {
   // Scan for all "enable" type proxy switches.
   static const char* proxy_switches[] = {
@@ -86,10 +107,33 @@
   return proxy_config;
 }
 
+static net::ProxyConfigService* CreateProxyConfigService(
+    const CommandLine& command_line) {
+  // The linux gconf-based proxy settings getter relies on being initialized
+  // from the UI thread.
+  CheckCurrentlyOnMainThread();
+
+  scoped_ptr<net::ProxyConfig> proxy_config_from_cmd_line(
+      CreateProxyConfig(command_line));
+
+  if (!proxy_config_from_cmd_line.get()) {
+    // Use system settings.
+    return net::ProxyService::CreateSystemProxyConfigService(
+        g_browser_process->io_thread()->message_loop(),
+        g_browser_process->file_thread()->message_loop());
+  }
+
+  // Otherwise use the fixed settings from the command line.
+  return new net::ProxyConfigServiceFixed(*proxy_config_from_cmd_line.get());
+}
+
 // Create a proxy service according to the options on command line.
-static net::ProxyService* CreateProxyService(URLRequestContext* context,
-                                             const CommandLine& command_line) {
-  scoped_ptr<net::ProxyConfig> proxy_config(CreateProxyConfig(command_line));
+static net::ProxyService* CreateProxyService(
+    URLRequestContext* context,
+    net::ProxyConfigService* proxy_config_service,
+    const CommandLine& command_line,
+    MessageLoop* io_loop) {
+  CheckCurrentlyOnIOThread();
 
   bool use_v8 = !command_line.HasSwitch(switches::kWinHttpProxyResolver);
   if (use_v8 && command_line.HasSwitch(switches::kSingleProcess)) {
@@ -100,38 +144,87 @@
   }
 
   return net::ProxyService::Create(
-      proxy_config.get(),
+      proxy_config_service,
       use_v8,
       context,
-      g_browser_process->io_thread()->message_loop(),
-      g_browser_process->file_thread()->message_loop());
+      io_loop);
 }
 
+// Lazily create a ChromeURLRequestContext using our factory.
+URLRequestContext* ChromeURLRequestContextGetter::GetURLRequestContext() {
+  CheckCurrentlyOnIOThread();
+
+  if (!url_request_context_) {
+    DCHECK(factory_.get());
+    url_request_context_ = factory_->Create();
+    factory_.reset();
+  }
+
+  return url_request_context_;
+}
+
+// Factory that creates the main ChromeURLRequestContext.
+class FactoryForOriginal : public ChromeURLRequestContextFactory {
+ public:
+  FactoryForOriginal(Profile* profile,
+                     const FilePath& cookie_store_path,
+                     const FilePath& disk_cache_path,
+                     int cache_size)
+      : ChromeURLRequestContextFactory(profile),
+        cookie_store_path_(cookie_store_path),
+        disk_cache_path_(disk_cache_path),
+        cache_size_(cache_size),
+        // We need to initialize the ProxyConfigService from the UI thread
+        // because on linux it relies on initializing things through gconf,
+        // and needs to be on the main thread.
+        proxy_config_service_(
+            CreateProxyConfigService(
+                *CommandLine::ForCurrentProcess())) {
+  }
+
+  virtual ChromeURLRequestContext* Create();
+
+ private:
+  FilePath cookie_store_path_;
+  FilePath disk_cache_path_;
+  int cache_size_;
+
+  scoped_ptr<net::ProxyConfigService> proxy_config_service_;
+};
+
 // static
-ChromeURLRequestContext* ChromeURLRequestContext::CreateOriginal(
+ChromeURLRequestContextGetter* ChromeURLRequestContextGetter::CreateOriginal(
     Profile* profile, const FilePath& cookie_store_path,
-    const FilePath& disk_cache_path, int cache_size,
-    ChromeAppCacheService* appcache_service) {
+    const FilePath& disk_cache_path, int cache_size) {
   DCHECK(!profile->IsOffTheRecord());
-  ChromeURLRequestContext* context = new ChromeURLRequestContext(
-      profile, appcache_service);
+  return new ChromeURLRequestContextGetter(
+      profile,
+      new FactoryForOriginal(profile,
+                             cookie_store_path,
+                             disk_cache_path,
+                             cache_size));
+}
 
-  // The appcache service uses the profile's original context for UpdateJobs.
-  DCHECK(!appcache_service->request_context());
-  appcache_service->set_request_context(context);
+ChromeURLRequestContext* FactoryForOriginal::Create() {
+  ChromeURLRequestContext* context = new ChromeURLRequestContext;
+  ApplyProfileParametersToContext(context);
 
   // Global host resolver for the context.
-  context->host_resolver_ = chrome_browser_net::GetGlobalHostResolver();
+  context->set_host_resolver(chrome_browser_net::GetGlobalHostResolver());
 
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
-  context->proxy_service_ = CreateProxyService(context, command_line);
+  context->set_proxy_service(
+      CreateProxyService(context,
+                         proxy_config_service_.release(),
+                         command_line,
+                         MessageLoop::current() /*io_loop*/));
 
   net::HttpCache* cache =
-      new net::HttpCache(context->host_resolver_,
-                         context->proxy_service_,
-                         context->ssl_config_service_,
-                         disk_cache_path, cache_size);
+      new net::HttpCache(context->host_resolver(),
+                         context->proxy_service(),
+                         context->ssl_config_service(),
+                         disk_cache_path_, cache_size_);
 
   if (command_line.HasSwitch(switches::kDisableByteRangeSupport))
     cache->set_enable_range_support(false);
@@ -142,97 +235,145 @@
 
   if (record_mode || playback_mode) {
     // Don't use existing cookies and use an in-memory store.
-    context->cookie_store_ = new net::CookieMonster();
+    context->set_cookie_store(new net::CookieMonster());
     cache->set_mode(
         record_mode ? net::HttpCache::RECORD : net::HttpCache::PLAYBACK);
   }
-  context->http_transaction_factory_ = cache;
+  context->set_http_transaction_factory(cache);
 
   // The kWininetFtp switch is Windows specific because we have two FTP
   // implementations on Windows.
 #if defined(OS_WIN)
   if (!command_line.HasSwitch(switches::kWininetFtp))
-    context->ftp_transaction_factory_ =
-        new net::FtpNetworkLayer(context->host_resolver_);
+    context->set_ftp_transaction_factory(
+        new net::FtpNetworkLayer(context->host_resolver()));
 #else
-  context->ftp_transaction_factory_ =
-      new net::FtpNetworkLayer(context->host_resolver_);
+  context->set_ftp_transaction_factory(
+      new net::FtpNetworkLayer(context->host_resolver()));
 #endif
 
   // setup cookie store
-  if (!context->cookie_store_) {
-    DCHECK(!cookie_store_path.empty());
+  if (!context->cookie_store()) {
+    DCHECK(!cookie_store_path_.empty());
 
     scoped_refptr<SQLitePersistentCookieStore> cookie_db =
         new SQLitePersistentCookieStore(
-            cookie_store_path,
-            g_browser_process->db_thread()->message_loop());
-    context->cookie_store_ = new net::CookieMonster(cookie_db.get());
+            cookie_store_path_,
+            db_loop_);
+    context->set_cookie_store(new net::CookieMonster(cookie_db.get()));
   }
 
+  // Create a new AppCacheService (issues fetches through the
+  // main URLRequestContext that we just created).
+  context->set_appcache_service(
+      new ChromeAppCacheService(profile_dir_path_, false));
+  context->appcache_service()->set_request_context(context);
+
+#if defined(OS_LINUX)
+  // TODO(ukai): find a better way to set the URLRequestContext for OCSP.
+  net::SetURLRequestContextForOCSP(context);
+#endif
+
   return context;
 }
 
 // static
-ChromeURLRequestContext* ChromeURLRequestContext::CreateOriginalForMedia(
-    Profile* profile, const FilePath& disk_cache_path, int cache_size,
-    ChromeAppCacheService* appcache_service) {
+ChromeURLRequestContextGetter*
+ChromeURLRequestContextGetter::CreateOriginalForMedia(
+    Profile* profile, const FilePath& disk_cache_path, int cache_size) {
   DCHECK(!profile->IsOffTheRecord());
   return CreateRequestContextForMedia(profile, disk_cache_path, cache_size,
-                                      false, appcache_service);
+                                      false);
 }
 
+// Factory that creates the ChromeURLRequestContext for extensions.
+class FactoryForExtensions : public ChromeURLRequestContextFactory {
+ public:
+  FactoryForExtensions(Profile* profile, const FilePath& cookie_store_path)
+      : ChromeURLRequestContextFactory(profile),
+        cookie_store_path_(cookie_store_path) {
+  }
+
+  virtual ChromeURLRequestContext* Create();
+
+ private:
+  FilePath cookie_store_path_;
+};
+
 // static
-ChromeURLRequestContext* ChromeURLRequestContext::CreateOriginalForExtensions(
+ChromeURLRequestContextGetter*
+ChromeURLRequestContextGetter::CreateOriginalForExtensions(
     Profile* profile, const FilePath& cookie_store_path) {
   DCHECK(!profile->IsOffTheRecord());
-  ChromeURLRequestContext* context = new ChromeURLRequestContext(
-      profile, NULL);
+  return new ChromeURLRequestContextGetter(
+      profile,
+      new FactoryForExtensions(profile, cookie_store_path));
+}
 
+ChromeURLRequestContext* FactoryForExtensions::Create() {
+  ChromeURLRequestContext* context = new ChromeURLRequestContext;
+  ApplyProfileParametersToContext(context);
+
   // All we care about for extensions is the cookie store.
-  DCHECK(!cookie_store_path.empty());
+  DCHECK(!cookie_store_path_.empty());
 
   scoped_refptr<SQLitePersistentCookieStore> cookie_db =
-      new SQLitePersistentCookieStore(
-          cookie_store_path,
-          g_browser_process->db_thread()->message_loop());
+      new SQLitePersistentCookieStore(cookie_store_path_, db_loop_);
   net::CookieMonster* cookie_monster = new net::CookieMonster(cookie_db.get());
 
   // Enable cookies for extension URLs only.
   const char* schemes[] = {chrome::kExtensionScheme};
   cookie_monster->SetCookieableSchemes(schemes, 1);
-  context->cookie_store_ = cookie_monster;
+  context->set_cookie_store(cookie_monster);
 
   return context;
 }
 
+// Factory that creates the ChromeURLRequestContext for incognito profile.
+class FactoryForOffTheRecord : public ChromeURLRequestContextFactory {
+ public:
+  FactoryForOffTheRecord(Profile* profile)
+      : ChromeURLRequestContextFactory(profile),
+        original_context_getter_(
+            static_cast<ChromeURLRequestContextGetter*>(
+                profile->GetOriginalProfile()->GetRequestContext())) {
+  }
+
+  virtual ChromeURLRequestContext* Create();
+
+ private:
+  scoped_refptr<ChromeURLRequestContextGetter> original_context_getter_;
+};
+
 // static
-ChromeURLRequestContext* ChromeURLRequestContext::CreateOffTheRecord(
-    Profile* profile, ChromeAppCacheService* appcache_service) {
+ChromeURLRequestContextGetter* ChromeURLRequestContextGetter::CreateOffTheRecord(
+    Profile* profile) {
   DCHECK(profile->IsOffTheRecord());
-  ChromeURLRequestContext* context = new ChromeURLRequestContext(
-      profile, appcache_service);
+  return new ChromeURLRequestContextGetter(
+      profile, new FactoryForOffTheRecord(profile));
+}
 
-  // The appcache service uses the profile's original context for UpdateJobs.
-  DCHECK(!appcache_service->request_context());
-  appcache_service->set_request_context(context);
+ChromeURLRequestContext* FactoryForOffTheRecord::Create() {
+  ChromeURLRequestContext* context = new ChromeURLRequestContext;
+  ApplyProfileParametersToContext(context);
 
+  ChromeURLRequestContext* original_context =
+      original_context_getter_->GetIOContext();
+
   // Share the same proxy service and host resolver as the original profile.
   // TODO(eroman): although ProxyService is reference counted, this sharing
   // still has a subtle dependency on the lifespan of the original profile --
   // ProxyService holds a (non referencing) pointer to the URLRequestContext
   // it uses to download PAC scripts, which in this case is the original
   // profile...
-  context->host_resolver_ =
-      profile->GetOriginalProfile()->GetRequestContext()->host_resolver();
-  context->proxy_service_ =
-      profile->GetOriginalProfile()->GetRequestContext()->proxy_service();
+  context->set_host_resolver(original_context->host_resolver());
+  context->set_proxy_service(original_context->proxy_service());
 
   net::HttpCache* cache =
-      new net::HttpCache(context->host_resolver_, context->proxy_service_,
-                         context->ssl_config_service_, 0);
-  context->cookie_store_ = new net::CookieMonster;
-  context->http_transaction_factory_ = cache;
+      new net::HttpCache(context->host_resolver(), context->proxy_service(),
+                         context->ssl_config_service(), 0);
+  context->set_cookie_store(new net::CookieMonster);
+  context->set_http_transaction_factory(cache);
 
   if (CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kDisableByteRangeSupport))
@@ -242,69 +383,129 @@
   // implementations on Windows.
 #if defined(OS_WIN)
   if (!CommandLine::ForCurrentProcess()->HasSwitch(switches::kWininetFtp))
-    context->ftp_transaction_factory_ =
-        new net::FtpNetworkLayer(context->host_resolver_);
+    context->set_ftp_transaction_factory(
+        new net::FtpNetworkLayer(context->host_resolver()));
 #else
-  context->ftp_transaction_factory_ =
-      new net::FtpNetworkLayer(context->host_resolver_);
+  context->set_ftp_transaction_factory(
+      new net::FtpNetworkLayer(context->host_resolver()));
 #endif
 
+  // Create a separate AppCacheService for OTR mode.
+  context->set_appcache_service(
+      new ChromeAppCacheService(profile_dir_path_, true));
+  context->appcache_service()->set_request_context(context);
+
   return context;
 }
 
+// Factory that creates the ChromeURLRequestContext for extensions in incognito
+// mode.
+class FactoryForOffTheRecordExtensions
+    : public ChromeURLRequestContextFactory {
+ public:
+  FactoryForOffTheRecordExtensions(Profile* profile)
+      : ChromeURLRequestContextFactory(profile) {}
+
+  virtual ChromeURLRequestContext* Create();
+};
+
 // static
-ChromeURLRequestContext*
-ChromeURLRequestContext::CreateOffTheRecordForExtensions(Profile* profile) {
+ChromeURLRequestContextGetter*
+ChromeURLRequestContextGetter::CreateOffTheRecordForExtensions(Profile* profile) {
   DCHECK(profile->IsOffTheRecord());
-  ChromeURLRequestContext* context =
-      new ChromeURLRequestContext(profile, NULL);
+  return new ChromeURLRequestContextGetter(
+      profile,
+      new FactoryForOffTheRecordExtensions(profile));
+}
+
+ChromeURLRequestContext* FactoryForOffTheRecordExtensions::Create() {
+  ChromeURLRequestContext* context = new ChromeURLRequestContext;
+  ApplyProfileParametersToContext(context);
+
   net::CookieMonster* cookie_monster = new net::CookieMonster;
 
   // Enable cookies for extension URLs only.
   const char* schemes[] = {chrome::kExtensionScheme};
   cookie_monster->SetCookieableSchemes(schemes, 1);
-  context->cookie_store_ = cookie_monster;
+  context->set_cookie_store(cookie_monster);
 
   return context;
 }
 
+// Factory that creates the ChromeURLRequestContext for media.
+class FactoryForMedia : public ChromeURLRequestContextFactory {
+ public:
+  FactoryForMedia(Profile* profile,
+                  const FilePath& disk_cache_path,
+                  int cache_size,
+                  bool off_the_record)
+      : ChromeURLRequestContextFactory(profile),
+        main_context_getter_(
+            static_cast<ChromeURLRequestContextGetter*>(
+                profile->GetRequestContext())) {
+    is_media_ = true;
+    is_off_the_record_ = off_the_record;
+  }
+
+  virtual ChromeURLRequestContext* Create();
+
+ private:
+  scoped_refptr<ChromeURLRequestContextGetter> main_context_getter_;
+
+  FilePath disk_cache_path_;
+  int cache_size_;
+};
+
 // static
-ChromeURLRequestContext* ChromeURLRequestContext::CreateRequestContextForMedia(
+ChromeURLRequestContextGetter*
+ChromeURLRequestContextGetter::CreateRequestContextForMedia(
     Profile* profile, const FilePath& disk_cache_path, int cache_size,
-    bool off_the_record, ChromeAppCacheService* appcache_service) {
-  URLRequestContext* original_context =
-      profile->GetOriginalProfile()->GetRequestContext();
-  ChromeURLRequestContext* context =
-      new ChromeURLRequestContext(profile, appcache_service);
-  context->is_media_ = true;
+    bool off_the_record) {
+  return new ChromeURLRequestContextGetter(
+      profile,
+      new FactoryForMedia(profile,
+                          disk_cache_path,
+                          cache_size,
+                          off_the_record));
+}
 
+ChromeURLRequestContext* FactoryForMedia::Create() {
+  ChromeURLRequestContext* context = new ChromeURLRequestContext;
+  ApplyProfileParametersToContext(context);
+
+  ChromeURLRequestContext* main_context =
+      main_context_getter_->GetIOContext();
+
   // Share the same proxy service of the common profile.
-  context->proxy_service_ = original_context->proxy_service();
+  context->set_proxy_service(main_context->proxy_service());
   // Also share the cookie store of the common profile.
-  context->cookie_store_ = original_context->cookie_store();
+  context->set_cookie_store(main_context->cookie_store());
 
   // Create a media cache with default size.
   // TODO(hclam): make the maximum size of media cache configurable.
-  net::HttpCache* original_cache =
-      original_context->http_transaction_factory()->GetCache();
+  net::HttpCache* main_cache =
+      main_context->http_transaction_factory()->GetCache();
   net::HttpCache* cache;
-  if (original_cache) {
-    // Try to reuse HttpNetworkSession in the original context, assuming that
+  if (main_cache) {
+    // Try to reuse HttpNetworkSession in the main context, assuming that
     // HttpTransactionFactory (network_layer()) of HttpCache is implemented
     // by HttpNetworkLayer so we can reuse HttpNetworkSession within it. This
     // assumption will be invalid if the original HttpCache is constructed with
     // HttpCache(HttpTransactionFactory*, disk_cache::Backend*) constructor.
-    net::HttpNetworkLayer* original_network_layer =
-        static_cast<net::HttpNetworkLayer*>(original_cache->network_layer());
-    cache = new net::HttpCache(original_network_layer->GetSession(),
-                               disk_cache_path, cache_size);
+    net::HttpNetworkLayer* main_network_layer =
+        static_cast<net::HttpNetworkLayer*>(main_cache->network_layer());
+    cache = new net::HttpCache(main_network_layer->GetSession(),
+                               disk_cache_path_, cache_size_);
+    // TODO(eroman): Since this is poaching the session from the main
+    // context, it should hold a reference to that context preventing the
+    // session from getting deleted.
   } else {
     // If original HttpCache doesn't exist, simply construct one with a whole
     // new set of network stack.
-    cache = new net::HttpCache(original_context->host_resolver(),
-                               original_context->proxy_service(),
-                               original_context->ssl_config_service(),
-                               disk_cache_path, cache_size);
+    cache = new net::HttpCache(main_context->host_resolver(),
+                               main_context->proxy_service(),
+                               main_context->ssl_config_service(),
+                               disk_cache_path_, cache_size_);
   }
 
   if (CommandLine::ForCurrentProcess()->HasSwitch(
@@ -312,21 +513,42 @@
     cache->set_enable_range_support(false);
 
   cache->set_type(net::MEDIA_CACHE);
-  context->http_transaction_factory_ = cache;
+  context->set_http_transaction_factory(cache);
+
+  // Use the same appcache service as the profile's main context.
+  context->set_appcache_service(main_context->appcache_service());
+
   return context;
 }
 
-ChromeURLRequestContext::ChromeURLRequestContext(
-    Profile* profile, ChromeAppCacheService* appcache_service)
-    : appcache_service_(appcache_service),
-      prefs_(profile->GetPrefs()),
-      is_media_(false),
+ChromeURLRequestContextGetter::ChromeURLRequestContextGetter(
+    Profile* profile,
+    ChromeURLRequestContextFactory* factory)
+  : prefs_(NULL),
+    factory_(factory),
+    url_request_context_(NULL) {
+  DCHECK(factory);
+
+  // If a base profile was specified, listen for changes to the preferences.
+  if (profile)
+    RegisterPrefsObserver(profile);
+}
+
+// Extract values from |profile| and copy them into
+// ChromeURLRequestContextFactory. We will use them later when constructing the
+// ChromeURLRequestContext on the IO thread (see
+// ApplyProfileParametersToContext() which reverses this).
+ChromeURLRequestContextFactory::ChromeURLRequestContextFactory(Profile* profile)
+    : is_media_(false),
       is_off_the_record_(profile->IsOffTheRecord()) {
+  CheckCurrentlyOnMainThread();
+  PrefService* prefs = profile->GetPrefs();
+
   // Set up Accept-Language and Accept-Charset header values
   accept_language_ = net::HttpUtil::GenerateAcceptLanguageHeader(
-      WideToASCII(prefs_->GetString(prefs::kAcceptLanguages)));
+      WideToASCII(prefs->GetString(prefs::kAcceptLanguages)));
   std::string default_charset =
-      WideToASCII(prefs_->GetString(prefs::kDefaultCharset));
+      WideToASCII(prefs->GetString(prefs::kDefaultCharset));
   accept_charset_ =
       net::HttpUtil::GenerateAcceptCharsetHeader(default_charset);
 
@@ -344,11 +566,13 @@
   // net_util::GetSuggestedFilename is unlikely to be taken.
   referrer_charset_ = default_charset;
 
-  cookie_policy_.set_type(net::CookiePolicy::FromInt(
-      prefs_->GetInteger(prefs::kCookieBehavior)));
+  cookie_policy_type_ = net::CookiePolicy::FromInt(
+      prefs->GetInteger(prefs::kCookieBehavior));
 
+  // TODO(eroman): this doesn't look safe; sharing between IO and UI threads!
   blacklist_ = profile->GetBlacklist();
 
+  // TODO(eroman): this doesn't look safe; sharing between IO and UI threads!
   strict_transport_security_state_ = profile->GetStrictTransportSecurityState();
 
   if (profile->GetExtensionsService()) {
@@ -363,15 +587,51 @@
   if (profile->GetUserScriptMaster())
     user_script_dir_path_ = profile->GetUserScriptMaster()->user_script_dir();
 
+  // TODO(eroman): this doesn't look safe; sharing between IO and UI threads!
+  ssl_config_service_ = profile->GetSSLConfigService();
+
+  profile_dir_path_ = profile->GetPath();
+
+  // Get references to the database and file threads.
+  db_loop_ = g_browser_process->db_thread()->message_loop();
+}
+
+ChromeURLRequestContextFactory::~ChromeURLRequestContextFactory() {
+  CheckCurrentlyOnIOThread();
+}
+
+void ChromeURLRequestContextFactory::ApplyProfileParametersToContext(
+    ChromeURLRequestContext* context) {
+  // Apply all the parameters. NOTE: keep this in sync with
+  // ChromeURLRequestContextFactory(Profile*).
+  context->set_is_media(is_media_);
+  context->set_is_off_the_record(is_off_the_record_);
+  context->set_accept_language(accept_language_);
+  context->set_accept_charset(accept_charset_);
+  context->set_referrer_charset(referrer_charset_);
+  context->set_cookie_policy_type(cookie_policy_type_);
+  context->set_extension_paths(extension_paths_);
+  context->set_user_script_dir_path(user_script_dir_path_);
+  context->set_blacklist(blacklist_);
+  context->set_strict_transport_security_state(
+      strict_transport_security_state_);
+  context->set_ssl_config_service(ssl_config_service_);
+}
+
+void ChromeURLRequestContextGetter::RegisterPrefsObserver(Profile* profile) {
+  CheckCurrentlyOnMainThread();
+
+  prefs_ = profile->GetPrefs();
+
   prefs_->AddPrefObserver(prefs::kAcceptLanguages, this);
   prefs_->AddPrefObserver(prefs::kCookieBehavior, this);
   prefs_->AddPrefObserver(prefs::kDefaultCharset, this);
-
-  ssl_config_service_ = profile->GetSSLConfigService();
 }
 
 ChromeURLRequestContext::ChromeURLRequestContext(
     ChromeURLRequestContext* other) {
+  CheckCurrentlyOnIOThread();
+
   // Set URLRequestContext members
   host_resolver_ = other->host_resolver_;
   proxy_service_ = other->proxy_service_;
@@ -389,16 +649,17 @@
   appcache_service_ = other->appcache_service_;
   extension_paths_ = other->extension_paths_;
   user_script_dir_path_ = other->user_script_dir_path_;
-  prefs_ = other->prefs_;
   blacklist_ = other->blacklist_;
   is_media_ = other->is_media_;
   is_off_the_record_ = other->is_off_the_record_;
 }
 
 // NotificationObserver implementation.
-void ChromeURLRequestContext::Observe(NotificationType type,
-                                      const NotificationSource& source,
-                                      const NotificationDetails& details) {
+void ChromeURLRequestContextGetter::Observe(NotificationType type,
+                                   const NotificationSource& source,
+                                   const NotificationDetails& details) {
+  CheckCurrentlyOnMainThread();
+
   if (NotificationType::PREF_CHANGED == type) {
     std::wstring* pref_name_in = Details<std::wstring>(details).ptr();
     PrefService* prefs = Source<PrefService>(source).ptr();
@@ -407,39 +668,91 @@
       std::string accept_language =
           WideToASCII(prefs->GetString(prefs::kAcceptLanguages));
       g_browser_process->io_thread()->message_loop()->PostTask(FROM_HERE,
-          NewRunnableMethod(this,
-                            &ChromeURLRequestContext::OnAcceptLanguageChange,
-                            accept_language));
+          NewRunnableMethod(
+              this,
+              &ChromeURLRequestContextGetter::OnAcceptLanguageChange,
+              accept_language));
     } else if (*pref_name_in == prefs::kCookieBehavior) {
       net::CookiePolicy::Type policy_type = net::CookiePolicy::FromInt(
           prefs_->GetInteger(prefs::kCookieBehavior));
       g_browser_process->io_thread()->message_loop()->PostTask(FROM_HERE,
-          NewRunnableMethod(this,
-                            &ChromeURLRequestContext::OnCookiePolicyChange,
-                            policy_type));
+          NewRunnableMethod(
+              this,
+              &ChromeURLRequestContextGetter::OnCookiePolicyChange,
+              policy_type));
     } else if (*pref_name_in == prefs::kDefaultCharset) {
       std::string default_charset =
           WideToASCII(prefs->GetString(prefs::kDefaultCharset));
       g_browser_process->io_thread()->message_loop()->PostTask(FROM_HERE,
-          NewRunnableMethod(this,
-                            &ChromeURLRequestContext::OnDefaultCharsetChange,
-                            default_charset));
+          NewRunnableMethod(
+              this,
+              &ChromeURLRequestContextGetter::OnDefaultCharsetChange,
+              default_charset));
     }
   } else {
     NOTREACHED();
   }
 }
 
-void ChromeURLRequestContext::CleanupOnUIThread() {
-  // Unregister for pref notifications.
-  prefs_->RemovePrefObserver(prefs::kAcceptLanguages, this);
-  prefs_->RemovePrefObserver(prefs::kCookieBehavior, this);
-  prefs_->RemovePrefObserver(prefs::kDefaultCharset, this);
-  prefs_ = NULL;
+void ChromeURLRequestContextGetter::OnAcceptLanguageChange(
+    const std::string& accept_language) {
+  GetIOContext()->OnAcceptLanguageChange(accept_language);
+}
 
+void ChromeURLRequestContextGetter::OnCookiePolicyChange(
+    net::CookiePolicy::Type type) {
+  GetIOContext()->OnCookiePolicyChange(type);
+}
+
+void ChromeURLRequestContextGetter::OnDefaultCharsetChange(
+    const std::string& default_charset) {
+  GetIOContext()->OnDefaultCharsetChange(default_charset);
+}
+
+void ChromeURLRequestContextGetter::OnNewExtensions(const std::string& id,
+                                                    const FilePath& path) {
+  GetIOContext()->OnNewExtensions(id, path);
+}
+
+void ChromeURLRequestContextGetter::OnUnloadedExtension(
+    const std::string& id) {
+  GetIOContext()->OnUnloadedExtension(id);
+}
+
+void ChromeURLRequestContextGetter::CleanupOnUIThread() {
+  CheckCurrentlyOnMainThread();
+
+  if (prefs_) {
+    // Unregister for pref notifications.
+    prefs_->RemovePrefObserver(prefs::kAcceptLanguages, this);
+    prefs_->RemovePrefObserver(prefs::kCookieBehavior, this);
+    prefs_->RemovePrefObserver(prefs::kDefaultCharset, this);
+    prefs_ = NULL;
+  }
+
+  // TODO(eroman): Doesn't look like this member is even used...
+  // can probably be deleted.
   registrar_.RemoveAll();
 }
 
+ChromeURLRequestContextGetter::~ChromeURLRequestContextGetter() {
+  CheckCurrentlyOnIOThread();
+
+  DCHECK(!prefs_) << "Probably didn't call CleanupOnUIThread";
+
+  // Either we already transformed the factory into a URLRequestContext, or
+  // we still have a pending factory.
+  DCHECK((factory_.get() && !url_request_context_.get()) ||
+         (!factory_.get() && url_request_context_.get()));
+
+  // The scoped_refptr / scoped_ptr destructors take care of releasing
+  // |factory_| and |url_request_context_| now.
+}
+
+ChromeURLRequestContext::ChromeURLRequestContext() {
+  CheckCurrentlyOnIOThread();
+}
+
 FilePath ChromeURLRequestContext::GetPathForExtension(const std::string& id) {
   ExtensionPaths::iterator iter = extension_paths_.find(id);
   if (iter != extension_paths_.end()) {
@@ -496,23 +809,20 @@
 
 void ChromeURLRequestContext::OnAcceptLanguageChange(
     const std::string& accept_language) {
-  DCHECK(MessageLoop::current() ==
-         ChromeThread::GetMessageLoop(ChromeThread::IO));
+  CheckCurrentlyOnIOThread();
   accept_language_ =
       net::HttpUtil::GenerateAcceptLanguageHeader(accept_language);
 }
 
 void ChromeURLRequestContext::OnCookiePolicyChange(
     net::CookiePolicy::Type type) {
-  DCHECK(MessageLoop::current() ==
-         ChromeThread::GetMessageLoop(ChromeThread::IO));
+  CheckCurrentlyOnIOThread();
   cookie_policy_.set_type(type);
 }
 
 void ChromeURLRequestContext::OnDefaultCharsetChange(
     const std::string& default_charset) {
-  DCHECK(MessageLoop::current() ==
-         ChromeThread::GetMessageLoop(ChromeThread::IO));
+  CheckCurrentlyOnIOThread();
   referrer_charset_ = default_charset;
   accept_charset_ =
       net::HttpUtil::GenerateAcceptCharsetHeader(default_charset);
@@ -525,6 +835,7 @@
 }
 
 void ChromeURLRequestContext::OnUnloadedExtension(const std::string& id) {
+  CheckCurrentlyOnIOThread();
   if (is_off_the_record_)
     return;
   ExtensionPaths::iterator iter = extension_paths_.find(id);
@@ -533,8 +844,7 @@
 }
 
 ChromeURLRequestContext::~ChromeURLRequestContext() {
-  DCHECK(NULL == prefs_);
-
+  CheckCurrentlyOnIOThread();
   if (appcache_service_.get() && appcache_service_->request_context() == this)
     appcache_service_->set_request_context(NULL);
 
@@ -546,3 +856,35 @@
   delete ftp_transaction_factory_;
   delete http_transaction_factory_;
 }
+
+net::CookieStore* ChromeURLRequestContextGetter::GetCookieStore() {
+  // If we are running on the IO thread this is real easy.
+  if (ChromeThread::CurrentlyOn(ChromeThread::IO))
+    return GetURLRequestContext()->cookie_store();
+
+  // If we aren't running on the IO thread, we cannot call
+  // GetURLRequestContext(). Instead we will post a task to the IO loop
+  // and wait for it to complete.
+
+  base::WaitableEvent completion(false, false);
+  net::CookieStore* result = NULL;
+
+  g_browser_process->io_thread()->message_loop()->PostTask(
+      FROM_HERE,
+      NewRunnableMethod(this,
+          &ChromeURLRequestContextGetter::GetCookieStoreAsyncHelper,
+          &completion,
+          &result));
+
+  completion.Wait();
+  DCHECK(result);
+  return result;
+}
+
+void ChromeURLRequestContextGetter::GetCookieStoreAsyncHelper(
+    base::WaitableEvent* completion,
+    net::CookieStore** result) {
+  // Note that CookieStore is refcounted, yet we do not add a reference.
+  *result = GetURLRequestContext()->cookie_store();
+  completion->Signal();
+}