Revert 74292 - Splits ChromeURLDataManager into 2 chunks:

. ChromeURLDataManager is no longer a singleton and is always used on
  the UI thread. ChromeURLDataManager is now profile specific (you get
  from the profile).
. ChromeURLDataManagerBackend handles the URLRequests and the
  DataSources. ChromeURLDataManagerBackend is created by
  ChromeURLRequestContext.

All DataSources are now profile specific. There were two that wanted
to be global, but have been converted.

BUG=52022 71868
TEST=none

Review URL: http://codereview.chromium.org/6286131

TBR=sky@chromium.org
Review URL: http://codereview.chromium.org/6461024

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@74294 0039d316-1c4b-4281-b951-d872f2087c98

57 files changed, 856 insertions, 816 deletions

diff --git a/chrome/browser/browser_about_handler.cc b/chrome/browser/browser_about_handler.cc
index c4747d9..9e7b48c 100644
--- a/chrome/browser/browser_about_handler.cc
+++ b/chrome/browser/browser_about_handler.cc
@@ -160,6 +160,9 @@ const char *kAllAboutPaths[] = {
 #endif
   };
 
+// Points to the singleton AboutSource object, if any.
+ChromeURLDataManager::DataSource* about_source = NULL;
+
 // When you type about:memory, it actually loads an intermediate URL that
 // redirects you to the final page. This avoids the problem where typing
 // "about:memory" on the new tab page or any other page where a process
@@ -689,9 +692,21 @@ std::string VersionNumberToString(uint32 value) {
 
 AboutSource::AboutSource()
     : DataSource(chrome::kAboutScheme, MessageLoop::current()) {
+  // This should be a singleton.
+  DCHECK(!about_source);
+  about_source = this;
+
+  // Add us to the global URL handler on the IO thread.
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(this)));
 }
 
 AboutSource::~AboutSource() {
+  about_source = NULL;
 }
 
 void AboutSource::StartDataRequest(const std::string& path_raw,
@@ -1039,7 +1054,7 @@ bool WillHandleBrowserAboutURL(GURL* url, Profile* profile) {
     return false;
 
   // Anything else requires our special handler; make sure it's initialized.
-  InitializeAboutDataSource(profile);
+  InitializeAboutDataSource();
 
   // Special case about:memory to go through a redirect before ending up on
   // the final page. See GetAboutMemoryRedirectResponse above for why.
@@ -1057,8 +1072,14 @@ bool WillHandleBrowserAboutURL(GURL* url, Profile* profile) {
   return true;
 }
 
-void InitializeAboutDataSource(Profile* profile) {
-  profile->GetChromeURLDataManager()->AddDataSource(new AboutSource());
+void InitializeAboutDataSource() {
+  // We only need to register the AboutSource once and it is kept globally.
+  // There is currently no way to remove a data source.
+  static bool initialized = false;
+  if (!initialized) {
+    about_source = new AboutSource();
+    initialized = true;
+  }
 }
 
 // This function gets called with the fixed-up chrome: URLs, so we have to
diff --git a/chrome/browser/browser_about_handler.h b/chrome/browser/browser_about_handler.h
index e5e31c9f..46ae100 100644
--- a/chrome/browser/browser_about_handler.h
+++ b/chrome/browser/browser_about_handler.h
@@ -28,7 +28,7 @@ bool WillHandleBrowserAboutURL(GURL* url, Profile* profile);
 
 // Register the data source for chrome://about URLs.
 // Safe to call multiple times.
-void InitializeAboutDataSource(Profile* profile);
+void InitializeAboutDataSource();
 
 // We have a few magic commands that don't cause navigations, but rather pop up
 // dialogs. This function handles those cases, and returns true if so. In this
diff --git a/chrome/browser/browser_about_handler_unittest.cc b/chrome/browser/browser_about_handler_unittest.cc
index 16fface..6b3bd40 100644
--- a/chrome/browser/browser_about_handler_unittest.cc
+++ b/chrome/browser/browser_about_handler_unittest.cc
@@ -5,10 +5,8 @@
 #include "base/basictypes.h"
 #include "base/scoped_ptr.h"
 #include "chrome/browser/browser_about_handler.h"
-#include "chrome/browser/browser_thread.h"
 #include "chrome/common/about_handler.h"
 #include "chrome/common/url_constants.h"
-#include "chrome/test/testing_profile.h"
 #include "googleurl/src/gurl.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -98,16 +96,13 @@ TEST(BrowserAboutHandlerTest, WillHandleBrowserAboutURL) {
         true
       },
   };
-  MessageLoopForUI message_loop;
-  BrowserThread ui_thread(BrowserThread::UI, &message_loop);
-  TestingProfile profile;
 
   for (size_t i = 0; i < ARRAYSIZE_UNSAFE(test_data); ++i) {
     GURL url(test_data[i].test_url);
     EXPECT_EQ(test_data[i].about_handled,
               chrome_about_handler::WillHandle(url));
     EXPECT_EQ(test_data[i].browser_handled,
-              WillHandleBrowserAboutURL(&url, &profile));
+              WillHandleBrowserAboutURL(&url, NULL));
     EXPECT_EQ(test_data[i].result_url, url);
   }
 
diff --git a/chrome/browser/browser_main.cc b/chrome/browser/browser_main.cc
index b0f3954..0819289 100644
--- a/chrome/browser/browser_main.cc
+++ b/chrome/browser/browser_main.cc
@@ -36,7 +36,7 @@
 #include "chrome/browser/browser_process_impl.h"
 #include "chrome/browser/browser_shutdown.h"
 #include "chrome/browser/browser_thread.h"
-#include "chrome/browser/dom_ui/chrome_url_data_manager_backend.h"
+#include "chrome/browser/dom_ui/chrome_url_data_manager.h"
 #include "chrome/browser/extensions/extension_protocols.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extensions_startup.h"
@@ -1548,7 +1548,7 @@ int BrowserMain(const MainFunctionParams& parameters) {
 
   // Register our global network handler for chrome:// and
   // chrome-extension:// URLs.
-  ChromeURLDataManagerBackend::Register();
+  RegisterURLRequestChromeJob();
   RegisterExtensionProtocols();
   RegisterMetadataURLRequestHandler();
   RegisterBlobURLRequestJobFactory();
diff --git a/chrome/browser/browser_shutdown.cc b/chrome/browser/browser_shutdown.cc
index 198a75c..7858c8f 100644
--- a/chrome/browser/browser_shutdown.cc
+++ b/chrome/browser/browser_shutdown.cc
@@ -257,11 +257,16 @@ void Shutdown() {
     file_util::WriteFile(shutdown_ms_file, shutdown_ms.c_str(), len);
   }
 
+  UnregisterURLRequestChromeJob();
+
 #if defined(OS_CHROMEOS)
   BrowserList::NotifyAndTerminate(false);
 #endif
 
-  ChromeURLDataManager::DeleteDataSources();
+  // Clean up data sources before the UI thread is removed.
+  ChromeURLDataManager* data_manager = ChromeURLDataManager::GetInstance();
+  if (data_manager)
+    data_manager->RemoveAllDataSources();
 }
 
 void ReadLastShutdownFile(
diff --git a/chrome/browser/browser_signin.cc b/chrome/browser/browser_signin.cc
index f077d0c..1c2c051 100644
--- a/chrome/browser/browser_signin.cc
+++ b/chrome/browser/browser_signin.cc
@@ -215,11 +215,12 @@ BrowserSignin::BrowserSignin(Profile* profile)
     : profile_(profile),
       delegate_(NULL),
       html_dialog_ui_delegate_(NULL) {
-  // profile is NULL during testing.
-  if (profile) {
-    BrowserSigninResourcesSource* source = new BrowserSigninResourcesSource();
-    profile->GetChromeURLDataManager()->AddDataSource(source);
-  }
+  BrowserSigninResourcesSource* source = new BrowserSigninResourcesSource();
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                        &ChromeURLDataManager::AddDataSource,
+                        make_scoped_refptr(source)));
 }
 
 BrowserSignin::~BrowserSignin() {
diff --git a/chrome/browser/chromeos/dom_ui/imageburner_ui.cc b/chrome/browser/chromeos/dom_ui/imageburner_ui.cc
index 8aaa576..758b47b 100644
--- a/chrome/browser/chromeos/dom_ui/imageburner_ui.cc
+++ b/chrome/browser/chromeos/dom_ui/imageburner_ui.cc
@@ -649,5 +649,10 @@ ImageBurnUI::ImageBurnUI(TabContents* contents) : DOMUI(contents) {
   ImageBurnHandler* handler = new ImageBurnHandler(contents);
   AddMessageHandler((handler)->Attach(this));
   ImageBurnUIHTMLSource* html_source = new ImageBurnUIHTMLSource();
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+       BrowserThread::IO, FROM_HERE,
+       NewRunnableMethod(
+           ChromeURLDataManager::GetInstance(),
+           &ChromeURLDataManager::AddDataSource,
+           make_scoped_refptr(html_source)));
 }
diff --git a/chrome/browser/chromeos/dom_ui/keyboard_overlay_ui.cc b/chrome/browser/chromeos/dom_ui/keyboard_overlay_ui.cc
index fb84ee2..8f41996 100644
--- a/chrome/browser/chromeos/dom_ui/keyboard_overlay_ui.cc
+++ b/chrome/browser/chromeos/dom_ui/keyboard_overlay_ui.cc
@@ -12,8 +12,6 @@
 #include "chrome/browser/chromeos/cros/input_method_library.h"
 #include "chrome/browser/chromeos/input_method/input_method_util.h"
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
-#include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/jstemplate_builder.h"
 #include "chrome/common/url_constants.h"
 #include "grit/browser_resources.h"
@@ -296,5 +294,10 @@ KeyboardOverlayUI::KeyboardOverlayUI(TabContents* contents)
   KeyboardOverlayUIHTMLSource* html_source = new KeyboardOverlayUIHTMLSource();
 
   // Set up the chrome://keyboardoverlay/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
diff --git a/chrome/browser/chromeos/dom_ui/login/login_ui.cc b/chrome/browser/chromeos/dom_ui/login/login_ui.cc
index a1ba4e0..845bf4b 100644
--- a/chrome/browser/chromeos/dom_ui/login/login_ui.cc
+++ b/chrome/browser/chromeos/dom_ui/login/login_ui.cc
@@ -14,8 +14,6 @@
 #include "chrome/browser/chromeos/dom_ui/login/authenticator_facade_cros.h"
 #include "chrome/browser/chromeos/dom_ui/login/login_ui.h"
 #include "chrome/browser/chromeos/dom_ui/login/login_ui_helpers.h"
-#include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/common/url_constants.h"
@@ -157,7 +155,12 @@ LoginUI::LoginUI(TabContents* contents)
   LoginUIHTMLSource* html_source =
       new LoginUIHTMLSource(MessageLoop::current());
 
-  contents->profile->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
 
 }  // namespace chromeos
diff --git a/chrome/browser/chromeos/dom_ui/menu_ui.cc b/chrome/browser/chromeos/dom_ui/menu_ui.cc
index 04adde5..741961a 100644
--- a/chrome/browser/chromeos/dom_ui/menu_ui.cc
+++ b/chrome/browser/chromeos/dom_ui/menu_ui.cc
@@ -20,7 +20,6 @@
 #include "chrome/browser/chromeos/views/native_menu_webui.h"
 #include "chrome/browser/chromeos/views/webui_menu_widget.h"
 #include "chrome/browser/dom_ui/web_ui_util.h"
-#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/browser/tab_contents/tab_contents_delegate.h"
 #include "chrome/common/url_constants.h"
@@ -532,8 +531,12 @@ MenuUI::MenuUI(TabContents* contents) : DOMUI(contents) {
   MenuHandler* handler = new MenuHandler();
   AddMessageHandler((handler)->Attach(this));
 
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(
-      CreateDataSource());
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(CreateDataSource())));
 }
 
 MenuUI::MenuUI(TabContents* contents, ChromeURLDataManager::DataSource* source)
@@ -541,7 +544,12 @@ MenuUI::MenuUI(TabContents* contents, ChromeURLDataManager::DataSource* source)
   MenuHandler* handler = new MenuHandler();
   AddMessageHandler((handler)->Attach(this));
 
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(source)));
 }
 
 void MenuUI::ModelUpdated(const ui::MenuModel* model) {
diff --git a/chrome/browser/chromeos/dom_ui/mobile_setup_ui.cc b/chrome/browser/chromeos/dom_ui/mobile_setup_ui.cc
index ac3688e..a6365cd 100644
--- a/chrome/browser/chromeos/dom_ui/mobile_setup_ui.cc
+++ b/chrome/browser/chromeos/dom_ui/mobile_setup_ui.cc
@@ -1323,5 +1323,10 @@ MobileSetupUI::MobileSetupUI(TabContents* contents) : DOMUI(contents) {
       new MobileSetupUIHTMLSource(service_path);
 
   // Set up the chrome://mobilesetup/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
diff --git a/chrome/browser/chromeos/dom_ui/network_menu_ui.cc b/chrome/browser/chromeos/dom_ui/network_menu_ui.cc
index 8e0defd..cea000d 100644
--- a/chrome/browser/chromeos/dom_ui/network_menu_ui.cc
+++ b/chrome/browser/chromeos/dom_ui/network_menu_ui.cc
@@ -13,7 +13,6 @@
 #include "chrome/browser/chromeos/views/native_menu_webui.h"
 #include "chrome/browser/chromeos/views/webui_menu_widget.h"
 #include "chrome/browser/dom_ui/web_ui_theme_source.h"
-#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/url_constants.h"
 #include "googleurl/src/gurl.h"
@@ -118,8 +117,13 @@ NetworkMenuUI::NetworkMenuUI(TabContents* contents)
   AddMessageHandler((handler)->Attach(this));
 
   // Set up chrome://theme/ source.
-  WebUIThemeSource* theme = new WebUIThemeSource(contents->profile());
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(theme);
+  WebUIThemeSource* theme = new WebUIThemeSource(GetProfile());
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(theme)));
 }
 
 bool NetworkMenuUI::ModelAction(const ui::MenuModel* model,
diff --git a/chrome/browser/chromeos/dom_ui/register_page_ui.cc b/chrome/browser/chromeos/dom_ui/register_page_ui.cc
index f3e4453..2434c03 100644
--- a/chrome/browser/chromeos/dom_ui/register_page_ui.cc
+++ b/chrome/browser/chromeos/dom_ui/register_page_ui.cc
@@ -21,7 +21,6 @@
 #include "chrome/browser/chromeos/login/wizard_controller.h"
 #include "chrome/browser/chromeos/version_loader.h"
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
-#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/url_constants.h"
 #include "googleurl/src/gurl.h"
@@ -324,5 +323,10 @@ RegisterPageUI::RegisterPageUI(TabContents* contents) : DOMUI(contents){
   RegisterPageUIHTMLSource* html_source = new RegisterPageUIHTMLSource();
 
   // Set up the chrome://register/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
diff --git a/chrome/browser/chromeos/dom_ui/system_info_ui.cc b/chrome/browser/chromeos/dom_ui/system_info_ui.cc
index 93b8456..87f01d2 100644
--- a/chrome/browser/chromeos/dom_ui/system_info_ui.cc
+++ b/chrome/browser/chromeos/dom_ui/system_info_ui.cc
@@ -18,8 +18,6 @@
 #include "chrome/browser/chromeos/cros/cros_library.h"
 #include "chrome/browser/chromeos/cros/syslogs_library.h"
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
-#include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/jstemplate_builder.h"
 #include "chrome/common/url_constants.h"
@@ -181,5 +179,10 @@ SystemInfoUI::SystemInfoUI(TabContents* contents) : DOMUI(contents) {
   SystemInfoUIHTMLSource* html_source = new SystemInfoUIHTMLSource();
 
   // Set up the chrome://system/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
diff --git a/chrome/browser/dom_ui/bookmarks_ui.cc b/chrome/browser/dom_ui/bookmarks_ui.cc
index 490b102..b615168 100644
--- a/chrome/browser/dom_ui/bookmarks_ui.cc
+++ b/chrome/browser/dom_ui/bookmarks_ui.cc
@@ -8,9 +8,7 @@
 #include "base/ref_counted_memory.h"
 #include "base/singleton.h"
 #include "chrome/browser/browser_thread.h"
-#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
-#include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/url_constants.h"
 #include "grit/theme_resources.h"
 #include "ui/base/resource/resource_bundle.h"
@@ -50,7 +48,12 @@ BookmarksUI::BookmarksUI(TabContents* contents) : DOMUI(contents) {
   BookmarksUIHTMLSource* html_source = new BookmarksUIHTMLSource();
 
   // Set up the chrome://bookmarks/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
 
 // static
diff --git a/chrome/browser/dom_ui/bug_report_ui.cc b/chrome/browser/dom_ui/bug_report_ui.cc
index d7cbd42..d64a100 100644
--- a/chrome/browser/dom_ui/bug_report_ui.cc
+++ b/chrome/browser/dom_ui/bug_report_ui.cc
@@ -21,7 +21,6 @@
 #include "chrome/browser/bug_report_data.h"
 #include "chrome/browser/bug_report_util.h"
 #include "chrome/browser/dom_ui/web_ui_screenshot_source.h"
-#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_list.h"
@@ -433,9 +432,9 @@ void BugReportData::SendReport() {
 //
 ////////////////////////////////////////////////////////////////////////////////
 BugReportHandler::BugReportHandler(TabContents* tab)
-    : tab_(tab),
-      screenshot_source_(NULL),
-      bug_report_(NULL)
+    : tab_(tab)
+    , screenshot_source_(NULL)
+    , bug_report_(NULL)
 #if defined(OS_CHROMEOS)
     , syslogs_handle_(0)
 #endif
@@ -455,8 +454,12 @@ void BugReportHandler::ClobberScreenshotsSource() {
   // Re-create our screenshots data source (this clobbers the last source)
   // setting the screenshot to NULL, effectively disabling the source
   // TODO(rkc): Once there is a method to 'remove' a source, change this code
-  tab_->profile()->GetChromeURLDataManager()->AddDataSource(
-      new WebUIScreenshotSource(NULL));
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(new WebUIScreenshotSource(NULL))));
 
   // clobber last screenshot
   if (browser::last_screenshot_png)
@@ -470,7 +473,12 @@ void BugReportHandler::SetupScreenshotsSource() {
         browser::last_screenshot_png);
 
   // Add the source to the data manager.
-  tab_->profile()->GetChromeURLDataManager()->AddDataSource(screenshot_source_);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(screenshot_source_)));
 }
 
 WebUIMessageHandler* BugReportHandler::Attach(DOMUI* dom_ui) {
@@ -741,5 +749,10 @@ BugReportUI::BugReportUI(TabContents* tab) : HtmlDialogUI(tab) {
   BugReportUIHTMLSource* html_source =
       new BugReportUIHTMLSource(handler->Init());
   // Set up the chrome://bugreport/ source.
-  tab->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
diff --git a/chrome/browser/dom_ui/chrome_url_data_manager.cc b/chrome/browser/dom_ui/chrome_url_data_manager.cc
index 703a5af..c5c38c7 100644
--- a/chrome/browser/dom_ui/chrome_url_data_manager.cc
+++ b/chrome/browser/dom_ui/chrome_url_data_manager.cc
@@ -4,113 +4,332 @@
 
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
 
-#include <vector>
-
+#include "base/file_util.h"
 #include "base/i18n/rtl.h"
 #include "base/message_loop.h"
+#include "base/path_service.h"
 #include "base/ref_counted_memory.h"
+#include "base/singleton.h"
+#include "base/stl_util-inl.h"
 #include "base/string_util.h"
-#include "base/synchronization/lock.h"
+#include "base/threading/thread.h"
 #include "base/values.h"
+#if defined(OS_WIN)
+#include "base/win/windows_version.h"
+#endif
+#include "chrome/browser/appcache/view_appcache_internals_job_factory.h"
 #include "chrome/browser/browser_thread.h"
-#include "chrome/browser/dom_ui/chrome_url_data_manager_backend.h"
+#include "chrome/browser/dom_ui/shared_resources_data_source.h"
 #include "chrome/browser/net/chrome_url_request_context.h"
-#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/net/view_blob_internals_job_factory.h"
+#include "chrome/browser/net/view_http_cache_job_factory.h"
+#include "chrome/common/chrome_paths.h"
+#include "chrome/common/ref_counted_util.h"
+#include "chrome/common/url_constants.h"
+#include "googleurl/src/url_util.h"
 #include "grit/platform_locale_settings.h"
+#include "net/base/io_buffer.h"
+#include "net/base/net_errors.h"
+#include "net/url_request/url_request.h"
+#include "net/url_request/url_request_file_job.h"
+#include "net/url_request/url_request_job.h"
 #include "ui/base/l10n/l10n_util.h"
 
-#if defined(OS_WIN)
-#include "base/win/windows_version.h"
-#endif
+// URLRequestChromeJob is a net::URLRequestJob that manages running
+// chrome-internal resource requests asynchronously.
+// It hands off URL requests to ChromeURLDataManager, which asynchronously
+// calls back once the data is available.
+class URLRequestChromeJob : public net::URLRequestJob {
+ public:
+  explicit URLRequestChromeJob(net::URLRequest* request);
 
-// static
-base::Lock ChromeURLDataManager::delete_lock_;
+  // net::URLRequestJob implementation.
+  virtual void Start();
+  virtual void Kill();
+  virtual bool ReadRawData(net::IOBuffer* buf, int buf_size, int *bytes_read);
+  virtual bool GetMimeType(std::string* mime_type) const;
+
+  // Called by ChromeURLDataManager to notify us that the data blob is ready
+  // for us.
+  void DataAvailable(RefCountedMemory* bytes);
+
+  void SetMimeType(const std::string& mime_type) {
+    mime_type_ = mime_type;
+  }
+
+ private:
+  virtual ~URLRequestChromeJob();
+
+  // Helper for Start(), to let us start asynchronously.
+  // (This pattern is shared by most net::URLRequestJob implementations.)
+  void StartAsync();
+
+  // Do the actual copy from data_ (the data we're serving) into |buf|.
+  // Separate from ReadRawData so we can handle async I/O.
+  void CompleteRead(net::IOBuffer* buf, int buf_size, int* bytes_read);
+
+  // The actual data we're serving.  NULL until it's been fetched.
+  scoped_refptr<RefCountedMemory> data_;
+  // The current offset into the data that we're handing off to our
+  // callers via the Read interfaces.
+  int data_offset_;
+
+  // For async reads, we keep around a pointer to the buffer that
+  // we're reading into.
+  scoped_refptr<net::IOBuffer> pending_buf_;
+  int pending_buf_size_;
+  std::string mime_type_;
+
+  DISALLOW_COPY_AND_ASSIGN(URLRequestChromeJob);
+};
+
+// URLRequestChromeFileJob is a net::URLRequestJob that acts like a file:// URL
+class URLRequestChromeFileJob : public net::URLRequestFileJob {
+ public:
+  URLRequestChromeFileJob(net::URLRequest* request, const FilePath& path);
+
+ private:
+  virtual ~URLRequestChromeFileJob();
+
+  DISALLOW_COPY_AND_ASSIGN(URLRequestChromeFileJob);
+};
+
+void RegisterURLRequestChromeJob() {
+  FilePath inspector_dir;
+  if (PathService::Get(chrome::DIR_INSPECTOR, &inspector_dir)) {
+    ChromeURLDataManager::GetInstance()->AddFileSource(
+        chrome::kChromeUIDevToolsHost, inspector_dir);
+  }
+
+  SharedResourcesDataSource::Register();
+  net::URLRequest::RegisterProtocolFactory(chrome::kChromeDevToolsScheme,
+                                           &ChromeURLDataManager::Factory);
+  net::URLRequest::RegisterProtocolFactory(chrome::kChromeUIScheme,
+                                           &ChromeURLDataManager::Factory);
+}
+
+void UnregisterURLRequestChromeJob() {
+  FilePath inspector_dir;
+  if (PathService::Get(chrome::DIR_INSPECTOR, &inspector_dir)) {
+    ChromeURLDataManager::GetInstance()->RemoveFileSource(
+        chrome::kChromeUIDevToolsHost);
+  }
+}
 
 // static
-ChromeURLDataManager::DataSources* ChromeURLDataManager::data_sources_ = NULL;
+void ChromeURLDataManager::URLToRequest(const GURL& url,
+                                        std::string* source_name,
+                                        std::string* path) {
+  DCHECK(url.SchemeIs(chrome::kChromeDevToolsScheme) ||
+         url.SchemeIs(chrome::kChromeUIScheme));
+
+  if (!url.is_valid()) {
+    NOTREACHED();
+    return;
+  }
 
-// Invoked on the IO thread to do the actual adding of the DataSource.
-static void AddDataSourceOnIOThread(
-    scoped_refptr<URLRequestContextGetter> context_getter,
-    scoped_refptr<ChromeURLDataManager::DataSource> data_source) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  static_cast<ChromeURLRequestContext*>(
-      context_getter->GetURLRequestContext())->
-      GetChromeURLDataManagerBackend()->AddDataSource(data_source.get());
+  // Our input looks like: chrome://source_name/extra_bits?foo .
+  // So the url's "host" is our source, and everything after the host is
+  // the path.
+  source_name->assign(url.host());
+
+  const std::string& spec = url.possibly_invalid_spec();
+  const url_parse::Parsed& parsed = url.parsed_for_possibly_invalid_spec();
+  // + 1 to skip the slash at the beginning of the path.
+  int offset = parsed.CountCharactersBefore(url_parse::Parsed::PATH, false) + 1;
+
+  if (offset < static_cast<int>(spec.size()))
+    path->assign(spec.substr(offset));
 }
 
-ChromeURLDataManager::ChromeURLDataManager(Profile* profile)
-    : profile_(profile) {
+// static
+bool ChromeURLDataManager::URLToFilePath(const GURL& url,
+                                         FilePath* file_path) {
+  // Parse the URL into a request for a source and path.
+  std::string source_name;
+  std::string relative_path;
+
+  // Remove Query and Ref from URL.
+  GURL stripped_url;
+  GURL::Replacements replacements;
+  replacements.ClearQuery();
+  replacements.ClearRef();
+  stripped_url = url.ReplaceComponents(replacements);
+
+  URLToRequest(stripped_url, &source_name, &relative_path);
+
+  FileSourceMap::const_iterator i(
+      ChromeURLDataManager::GetInstance()->file_sources_.find(source_name));
+  if (i == ChromeURLDataManager::GetInstance()->file_sources_.end())
+    return false;
+
+  // Check that |relative_path| is not an absolute path (otherwise AppendASCII()
+  // will DCHECK). The awkward use of StringType is because on some systems
+  // FilePath expects a std::string, but on others a std::wstring.
+  FilePath p(FilePath::StringType(relative_path.begin(), relative_path.end()));
+  if (p.IsAbsolute())
+    return false;
+
+  *file_path = i->second.AppendASCII(relative_path);
+
+  return true;
 }
 
+ChromeURLDataManager::ChromeURLDataManager() : next_request_id_(0) { }
+
 ChromeURLDataManager::~ChromeURLDataManager() {
+  // This is used as a Singleton, so it is only called at exit cleanup time.
+  // This means it is called on the main (UI) thread.
+  //
+  // It will break if it is called at shutdown time on a different thread, as
+  // it will attempt to call the destructors for its |data_source_|s on the
+  // UI thread, but the UI thread's message loop will be not be running
+  // -- so the destructor calls will be dropped and we will leak the objects.
 }
 
-void ChromeURLDataManager::AddDataSource(DataSource* source) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  BrowserThread::PostTask(
-      BrowserThread::IO, FROM_HERE,
-      NewRunnableFunction(AddDataSourceOnIOThread,
-                          make_scoped_refptr(profile_->GetRequestContext()),
-                          make_scoped_refptr(source)));
+// static
+ChromeURLDataManager* ChromeURLDataManager::GetInstance() {
+  return Singleton<ChromeURLDataManager>::get();
 }
 
-// static
-void ChromeURLDataManager::DeleteDataSources() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DataSources sources;
-  {
-    base::AutoLock lock(delete_lock_);
-    data_sources_->swap(sources);
-  }
-  for (size_t i = 0; i < sources.size(); ++i)
-    delete sources[i];
+void ChromeURLDataManager::AddDataSource(scoped_refptr<DataSource> source) {
+  // Some |DataSource|-derived classes, notably |FileIconSource| and
+  // |WebUIFavIconSource|, have members that will DCHECK if they are not
+  // destructed in the same thread as they are constructed (the UI thread).
+  //
+  // If |AddDataSource| is called more than once, it will destruct the object
+  // that it had before, as it is the only thing still holding a reference to
+  // that object.  |DataSource| uses the |DeleteOnUIThread| trait to insure
+  // that the destructor is called on the UI thread.
+  //
+  // TODO(jackson): A new data source with same name should not clobber the
+  // existing one.
+  data_sources_[source->source_name()] = source;
 }
 
-// static
-void ChromeURLDataManager::DeleteDataSource(const DataSource* data_source) {
-  // Invoked when a DataSource is no longer referenced and needs to be deleted.
-  if (BrowserThread::CurrentlyOn(BrowserThread::UI)) {
-    // We're on the UI thread, delete right away.
-    delete data_source;
+void ChromeURLDataManager::RemoveDataSourceForTest(const char* source_name) {
+  DataSourceMap::iterator i = data_sources_.find(source_name);
+  if (i == data_sources_.end())
     return;
+  (*i).second = NULL;  // Calls Release().
+  data_sources_.erase(i);
+}
+
+void ChromeURLDataManager::RemoveAllDataSources() {
+  for (DataSourceMap::iterator i = data_sources_.begin();
+       i != data_sources_.end();
+       i = data_sources_.begin()) {
+    (*i).second = NULL;  // Calls Release().
+    data_sources_.erase(i);
+  }
+}
+
+void ChromeURLDataManager::AddFileSource(const std::string& source_name,
+                                         const FilePath& file_path) {
+  DCHECK(file_sources_.count(source_name) == 0);
+  file_sources_[source_name] = file_path;
+}
+
+void ChromeURLDataManager::RemoveFileSource(const std::string& source_name) {
+  DCHECK(file_sources_.count(source_name) == 1);
+  file_sources_.erase(source_name);
+}
+
+bool ChromeURLDataManager::HasPendingJob(URLRequestChromeJob* job) const {
+  for (PendingRequestMap::const_iterator i = pending_requests_.begin();
+       i != pending_requests_.end(); ++i) {
+    if (i->second == job)
+      return true;
+  }
+
+  return false;
+}
+
+bool ChromeURLDataManager::StartRequest(const GURL& url,
+                                        URLRequestChromeJob* job) {
+  // Parse the URL into a request for a source and path.
+  std::string source_name;
+  std::string path;
+  URLToRequest(url, &source_name, &path);
+
+  // Look up the data source for the request.
+  DataSourceMap::iterator i = data_sources_.find(source_name);
+  if (i == data_sources_.end())
+    return false;
+  DataSource* source = i->second;
+
+  // Save this request so we know where to send the data.
+  RequestID request_id = next_request_id_++;
+  pending_requests_.insert(std::make_pair(request_id, job));
+
+  // TODO(eroman): would be nicer if the mimetype were set at the same time
+  // as the data blob. For now do it here, since NotifyHeadersComplete() is
+  // going to get called once we return.
+  job->SetMimeType(source->GetMimeType(path));
+
+  ChromeURLRequestContext* context = static_cast<ChromeURLRequestContext*>(
+      job->request()->context());
+
+  // Forward along the request to the data source.
+  MessageLoop* target_message_loop = source->MessageLoopForRequestPath(path);
+  if (!target_message_loop) {
+    // The DataSource is agnostic to which thread StartDataRequest is called
+    // on for this path.  Call directly into it from this thread, the IO
+    // thread.
+    source->StartDataRequest(path, context->is_off_the_record(), request_id);
+  } else {
+    // The DataSource wants StartDataRequest to be called on a specific thread,
+    // usually the UI thread, for this path.
+    target_message_loop->PostTask(FROM_HERE,
+        NewRunnableMethod(source, &DataSource::StartDataRequest,
+                          path, context->is_off_the_record(), request_id));
   }
+  return true;
+}
 
-  // We're not on the UI thread, add the DataSource to the list of DataSources
-  // to delete.
-  bool schedule_delete = false;
-  {
-    base::AutoLock lock(delete_lock_);
-    if (!data_sources_)
-      data_sources_ = new DataSources();
-    schedule_delete = data_sources_->empty();
-    data_sources_->push_back(data_source);
+void ChromeURLDataManager::RemoveRequest(URLRequestChromeJob* job) {
+  // Remove the request from our list of pending requests.
+  // If/when the source sends the data that was requested, the data will just
+  // be thrown away.
+  for (PendingRequestMap::iterator i = pending_requests_.begin();
+       i != pending_requests_.end(); ++i) {
+    if (i->second == job) {
+      pending_requests_.erase(i);
+      return;
+    }
   }
-  if (schedule_delete) {
-    // Schedule a task to delete the DataSource back on the UI thread.
-    BrowserThread::PostTask(BrowserThread::UI,
-                            FROM_HERE,
-                            NewRunnableFunction(
-                                &ChromeURLDataManager::DeleteDataSources));
+}
+
+void ChromeURLDataManager::DataAvailable(
+    RequestID request_id,
+    scoped_refptr<RefCountedMemory> bytes) {
+  // Forward this data on to the pending net::URLRequest, if it exists.
+  PendingRequestMap::iterator i = pending_requests_.find(request_id);
+  if (i != pending_requests_.end()) {
+    // We acquire a reference to the job so that it doesn't disappear under the
+    // feet of any method invoked here (we could trigger a callback).
+    scoped_refptr<URLRequestChromeJob> job(i->second);
+    pending_requests_.erase(i);
+    job->DataAvailable(bytes);
   }
 }
 
 ChromeURLDataManager::DataSource::DataSource(const std::string& source_name,
                                              MessageLoop* message_loop)
-    : source_name_(source_name),
-      message_loop_(message_loop),
-      backend_(NULL) {
+    : source_name_(source_name), message_loop_(message_loop) {
 }
 
 ChromeURLDataManager::DataSource::~DataSource() {
 }
 
-void ChromeURLDataManager::DataSource::SendResponse(int request_id,
-                                                    RefCountedMemory* bytes) {
+void ChromeURLDataManager::DataSource::SendResponse(
+    RequestID request_id,
+    RefCountedMemory* bytes) {
   BrowserThread::PostTask(
       BrowserThread::IO, FROM_HERE,
-      NewRunnableMethod(this, &DataSource::SendResponseOnIOThread,
-                        request_id, make_scoped_refptr(bytes)));
+      NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                        &ChromeURLDataManager::DataAvailable,
+                        request_id, scoped_refptr<RefCountedMemory>(bytes)));
 }
 
 MessageLoop* ChromeURLDataManager::DataSource::MessageLoopForRequestPath(
@@ -138,10 +357,120 @@ void ChromeURLDataManager::DataSource::SetFontAndTextDirection(
       base::i18n::IsRTL() ? "rtl" : "ltr");
 }
 
-void ChromeURLDataManager::DataSource::SendResponseOnIOThread(
-    int request_id,
-    scoped_refptr<RefCountedMemory> bytes) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  if (backend_)
-    backend_->DataAvailable(request_id, bytes);
+net::URLRequestJob* ChromeURLDataManager::Factory(net::URLRequest* request,
+                                                  const std::string& scheme) {
+  // Try first with a file handler
+  FilePath path;
+  if (ChromeURLDataManager::URLToFilePath(request->url(), &path))
+    return new URLRequestChromeFileJob(request, path);
+
+  // Next check for chrome://view-http-cache/*, which uses its own job type.
+  if (ViewHttpCacheJobFactory::IsSupportedURL(request->url()))
+    return ViewHttpCacheJobFactory::CreateJobForRequest(request);
+
+  // Next check for chrome://appcache-internals/, which uses its own job type.
+  if (ViewAppCacheInternalsJobFactory::IsSupportedURL(request->url()))
+    return ViewAppCacheInternalsJobFactory::CreateJobForRequest(request);
+
+  // Next check for chrome://blob-internals/, which uses its own job type.
+  if (ViewBlobInternalsJobFactory::IsSupportedURL(request->url()))
+    return ViewBlobInternalsJobFactory::CreateJobForRequest(request);
+
+  // Fall back to using a custom handler
+  return new URLRequestChromeJob(request);
+}
+
+URLRequestChromeJob::URLRequestChromeJob(net::URLRequest* request)
+    : net::URLRequestJob(request),
+      data_offset_(0),
+      pending_buf_size_(0) {
+}
+
+URLRequestChromeJob::~URLRequestChromeJob() {
+  CHECK(!ChromeURLDataManager::GetInstance()->HasPendingJob(this));
 }
+
+void URLRequestChromeJob::Start() {
+  // Start reading asynchronously so that all error reporting and data
+  // callbacks happen as they would for network requests.
+  MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
+      this, &URLRequestChromeJob::StartAsync));
+}
+
+void URLRequestChromeJob::Kill() {
+  ChromeURLDataManager::GetInstance()->RemoveRequest(this);
+}
+
+bool URLRequestChromeJob::GetMimeType(std::string* mime_type) const {
+  *mime_type = mime_type_;
+  return !mime_type_.empty();
+}
+
+void URLRequestChromeJob::DataAvailable(RefCountedMemory* bytes) {
+  if (bytes) {
+    // The request completed, and we have all the data.
+    // Clear any IO pending status.
+    SetStatus(net::URLRequestStatus());
+
+    data_ = bytes;
+    int bytes_read;
+    if (pending_buf_.get()) {
+      CHECK(pending_buf_->data());
+      CompleteRead(pending_buf_, pending_buf_size_, &bytes_read);
+      pending_buf_ = NULL;
+      NotifyReadComplete(bytes_read);
+    }
+  } else {
+    // The request failed.
+    NotifyDone(net::URLRequestStatus(net::URLRequestStatus::FAILED,
+                                     net::ERR_FAILED));
+  }
+}
+
+bool URLRequestChromeJob::ReadRawData(net::IOBuffer* buf, int buf_size,
+                                      int* bytes_read) {
+  if (!data_.get()) {
+    SetStatus(net::URLRequestStatus(net::URLRequestStatus::IO_PENDING, 0));
+    DCHECK(!pending_buf_.get());
+    CHECK(buf->data());
+    pending_buf_ = buf;
+    pending_buf_size_ = buf_size;
+    return false;  // Tell the caller we're still waiting for data.
+  }
+
+  // Otherwise, the data is available.
+  CompleteRead(buf, buf_size, bytes_read);
+  return true;
+}
+
+void URLRequestChromeJob::CompleteRead(net::IOBuffer* buf, int buf_size,
+                                       int* bytes_read) {
+  int remaining = static_cast<int>(data_->size()) - data_offset_;
+  if (buf_size > remaining)
+    buf_size = remaining;
+  if (buf_size > 0) {
+    memcpy(buf->data(), data_->front() + data_offset_, buf_size);
+    data_offset_ += buf_size;
+  }
+  *bytes_read = buf_size;
+}
+
+void URLRequestChromeJob::StartAsync() {
+  if (!request_)
+    return;
+
+  if (ChromeURLDataManager::GetInstance()->StartRequest(request_->url(),
+                                                        this)) {
+    NotifyHeadersComplete();
+  } else {
+    NotifyStartError(net::URLRequestStatus(net::URLRequestStatus::FAILED,
+                                           net::ERR_INVALID_URL));
+  }
+}
+
+URLRequestChromeFileJob::URLRequestChromeFileJob(net::URLRequest* request,
+                                                 const FilePath& path)
+    : net::URLRequestFileJob(request, path) {
+}
+
+URLRequestChromeFileJob::~URLRequestChromeFileJob() { }
diff --git a/chrome/browser/dom_ui/chrome_url_data_manager.h b/chrome/browser/dom_ui/chrome_url_data_manager.h
index 163edf7..0717498 100644
--- a/chrome/browser/dom_ui/chrome_url_data_manager.h
+++ b/chrome/browser/dom_ui/chrome_url_data_manager.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2010 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.
 
@@ -9,45 +9,35 @@
 #include <map>
 #include <string>
 
+#include "base/singleton.h"
 #include "base/task.h"
 #include "base/ref_counted.h"
 #include "chrome/browser/browser_thread.h"
 
-class ChromeURLDataManagerBackend;
 class DictionaryValue;
 class FilePath;
+class GURL;
 class MessageLoop;
-class Profile;
 class RefCountedMemory;
+class URLRequestChromeJob;
+
+namespace net {
+class URLRequest;
+class URLRequestJob;
+}  // namespace net
 
 // To serve dynamic data off of chrome: URLs, implement the
 // ChromeURLDataManager::DataSource interface and register your handler
-// with AddDataSource. DataSources must be added on the UI thread (they are also
-// deleted on the UI thread). Internally the DataSources are maintained by
-// ChromeURLDataManagerBackend, see it for details.
+// with AddDataSource.
+
+// ChromeURLDataManager lives on the IO thread, so any interfacing with
+// it from the UI thread needs to go through an InvokeLater.
 class ChromeURLDataManager {
  public:
-  class DataSource;
+  // Returns the singleton instance.
+  static ChromeURLDataManager* GetInstance();
 
-  // Trait used to handle deleting a DataSource. Deletion happens on the UI
-  // thread.
-  //
-  // Implementation note: the normal shutdown sequence is for the UI loop to
-  // stop pumping events then the IO loop and thread are stopped. When the
-  // DataSources are no longer referenced (which happens when IO thread stops)
-  // they get added to the UI message loop for deletion. But because the UI loop
-  // has stopped by the time this happens the DataSources would be leaked.
-  //
-  // To make sure DataSources are properly deleted ChromeURLDataManager manages
-  // deletion of the DataSources.  When a DataSource is no longer referenced it
-  // is added to |data_sources_| and a task is posted to the UI thread to handle
-  // the actual deletion. During shutdown |DeleteDataSources| is invoked so that
-  // all pending DataSources are properly deleted.
-  struct DeleteDataSource {
-    static void Destruct(const DataSource* data_source) {
-      ChromeURLDataManager::DeleteDataSource(data_source);
-    }
-  };
+  typedef int RequestID;
 
   // A DataSource is an object that can answer requests for data
   // asynchronously. DataSources are collectively owned with refcounting smart
@@ -59,10 +49,11 @@ class ChromeURLDataManager {
   // StartDataRequest() by starting its (implementation-specific) asynchronous
   // request for the data, then call SendResponse() to notify.
   class DataSource : public base::RefCountedThreadSafe<
-      DataSource, DeleteDataSource> {
+      DataSource, BrowserThread::DeleteOnUIThread> {
    public:
     // See source_name_ and message_loop_ below for docs on these parameters.
-    DataSource(const std::string& source_name, MessageLoop* message_loop);
+    DataSource(const std::string& source_name,
+               MessageLoop* message_loop);
 
     // Sent by the DataManager to request data at |path|.  The source should
     // call SendResponse() when the data is available or if the request could
@@ -97,18 +88,13 @@ class ChromeURLDataManager {
     static void SetFontAndTextDirection(DictionaryValue* localized_strings);
 
    protected:
-    virtual ~DataSource();
-
-   private:
-    friend class ChromeURLDataManagerBackend;
-    friend class ChromeURLDataManager;
+    friend class base::RefCountedThreadSafe<DataSource>;
+    friend struct BrowserThread::DeleteOnThread<BrowserThread::UI>;
     friend class DeleteTask<DataSource>;
 
-    // SendResponse invokes this on the IO thread. Notifies the backend to
-    // handle the actual work of sending the data.
-    virtual void SendResponseOnIOThread(int request_id,
-                                        scoped_refptr<RefCountedMemory> bytes);
+    virtual ~DataSource();
 
+   private:
     // The name of this source.
     // E.g., for favicons, this could be "favicon", which results in paths for
     // specific resources like "favicon/34" getting sent to this source.
@@ -117,53 +103,89 @@ class ChromeURLDataManager {
     // The MessageLoop for the thread where this DataSource lives.
     // Used to send messages to the DataSource.
     MessageLoop* message_loop_;
-
-    // This field is set and maintained by ChromeURLDataManagerBackend. It is
-    // set when the DataSource is added, and unset if the DataSource is removed.
-    // A DataSource can be removed in two ways: the ChromeURLDataManagerBackend
-    // is deleted, or another DataSource is registered with the same
-    // name. backend_ should only be accessed on the IO thread.
-    // This reference can't be via a scoped_refptr else there would be a cycle
-    // between the backend and data source.
-    ChromeURLDataManagerBackend* backend_;
   };
 
-  explicit ChromeURLDataManager(Profile* profile);
-  ~ChromeURLDataManager();
-
-  // Adds a DataSource to the collection of data sources. This *must* be invoked
-  // on the UI thread.
-  //
-  // If |AddDataSource| is called more than once for a particular name it will
-  // release the old |DataSource|, most likely resulting in it getting deleted
-  // as there are no other references to it. |DataSource| uses the
-  // |DeleteOnUIThread| trait to insure that the destructor is called on the UI
-  // thread. This is necessary as some |DataSource|s notably |FileIconSource|
-  // and |WebUIFavIconSource|, have members that will DCHECK if they are not
-  // destructed in the same thread as they are constructed (the UI thread).
-  void AddDataSource(DataSource* source);
-
-  // Deletes any data sources no longer referenced. This is normally invoked
-  // for you, but can be invoked to force deletion (such as during shutdown).
-  static void DeleteDataSources();
+  // Add a DataSource to the collection of data sources.
+  // Because we don't track users of a given path, we can't know when it's
+  // safe to remove them, so the added source effectively leaks.
+  // This could be improved in the future but currently the users of this
+  // interface are conceptually permanent registration anyway.
+  // Adding a second DataSource with the same name clobbers the first.
+  // NOTE: Calling this from threads other the IO thread must be done via
+  // InvokeLater.
+  void AddDataSource(scoped_refptr<DataSource> source);
+  // Called during shutdown, before destruction of |BrowserThread|.
+  void RemoveDataSourceForTest(const char* source_name);  // For unit tests.
+  void RemoveAllDataSources();  // For the browser.
+
+  // Add/remove a path from the collection of file sources.
+  // A file source acts like a file:// URL to the specified path.
+  // Calling this from threads other the IO thread must be done via
+  // InvokeLater.
+  void AddFileSource(const std::string& source_name, const FilePath& path);
+  void RemoveFileSource(const std::string& source_name);
+
+  static net::URLRequestJob* Factory(net::URLRequest* request,
+                                     const std::string& scheme);
 
  private:
-  typedef std::vector<const ChromeURLDataManager::DataSource*> DataSources;
+  friend class URLRequestChromeJob;
+  friend struct DefaultSingletonTraits<ChromeURLDataManager>;
 
-  // If invoked on the UI thread the DataSource is deleted immediatlye,
-  // otherwise it is added to |data_sources_| and a task is scheduled to handle
-  // deletion on the UI thread. See note abouve DeleteDataSource for more info.
-  static void DeleteDataSource(const DataSource* data_source);
+  ChromeURLDataManager();
+  ~ChromeURLDataManager();
 
-  Profile* profile_;
+  // Parse a URL into the components used to resolve its request.
+  static void URLToRequest(const GURL& url,
+                           std::string* source,
+                           std::string* path);
+
+  // Translate a chrome resource URL into a local file path if there is one.
+  // Returns false if there is no file handler for this URL
+  static bool URLToFilePath(const GURL& url, FilePath* file_path);
+
+  // Called by the job when it's starting up.
+  // Returns false if |url| is not a URL managed by this object.
+  bool StartRequest(const GURL& url, URLRequestChromeJob* job);
+  // Remove a request from the list of pending requests.
+  void RemoveRequest(URLRequestChromeJob* job);
+
+  // Returns true if the job exists in |pending_requests_|. False otherwise.
+  // Called by ~URLRequestChromeJob to verify that |pending_requests_| is kept
+  // up to date.
+  bool HasPendingJob(URLRequestChromeJob* job) const;
+
+  // Sent by Request::SendResponse.
+  void DataAvailable(RequestID request_id,
+                     scoped_refptr<RefCountedMemory> bytes);
+
+  // File sources of data, keyed by source name (e.g. "inspector").
+  typedef std::map<std::string, FilePath> FileSourceMap;
+  FileSourceMap file_sources_;
+
+  // Custom sources of data, keyed by source path (e.g. "favicon").
+  typedef std::map<std::string, scoped_refptr<DataSource> > DataSourceMap;
+  DataSourceMap data_sources_;
+
+  // All pending URLRequestChromeJobs, keyed by ID of the request.
+  // URLRequestChromeJob calls into this object when it's constructed and
+  // destructed to ensure that the pointers in this map remain valid.
+  typedef std::map<RequestID, URLRequestChromeJob*> PendingRequestMap;
+  PendingRequestMap pending_requests_;
+
+  // The ID we'll use for the next request we receive.
+  RequestID next_request_id_;
+};
 
-  // Lock used when accessing |data_sources_|.
-  static base::Lock delete_lock_;
+// Since we have a single global ChromeURLDataManager, we don't need to
+// grab a reference to it when creating Tasks involving it.
+DISABLE_RUNNABLE_METHOD_REFCOUNT(ChromeURLDataManager);
 
-  // |data_sources_| that are no longer referenced and scheduled for deletion.
-  static DataSources* data_sources_;
+// Register our special URL handler under our special URL scheme.
+// Must be done once at startup.
+void RegisterURLRequestChromeJob();
 
-  DISALLOW_COPY_AND_ASSIGN(ChromeURLDataManager);
-};
+// Undoes the registration done by RegisterURLRequestChromeJob.
+void UnregisterURLRequestChromeJob();
 
 #endif  // CHROME_BROWSER_DOM_UI_CHROME_URL_DATA_MANAGER_H_
diff --git a/chrome/browser/dom_ui/chrome_url_data_manager_backend.cc b/chrome/browser/dom_ui/chrome_url_data_manager_backend.cc
deleted file mode 100644
index 0048828..0000000
--- a/chrome/browser/dom_ui/chrome_url_data_manager_backend.cc
+++ /dev/null
@@ -1,393 +0,0 @@
-// Copyright (c) 2011 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/dom_ui/chrome_url_data_manager_backend.h"
-
-#include "base/file_util.h"
-#include "base/message_loop.h"
-#include "base/path_service.h"
-#include "base/ref_counted_memory.h"
-#include "base/string_util.h"
-#include "chrome/browser/appcache/view_appcache_internals_job_factory.h"
-#include "chrome/browser/browser_thread.h"
-#include "chrome/browser/dom_ui/shared_resources_data_source.h"
-#include "chrome/browser/net/chrome_url_request_context.h"
-#include "chrome/browser/net/view_blob_internals_job_factory.h"
-#include "chrome/browser/net/view_http_cache_job_factory.h"
-#include "chrome/common/chrome_paths.h"
-#include "chrome/common/url_constants.h"
-#include "googleurl/src/url_util.h"
-#include "grit/platform_locale_settings.h"
-#include "net/base/io_buffer.h"
-#include "net/base/net_errors.h"
-#include "net/url_request/url_request.h"
-#include "net/url_request/url_request_file_job.h"
-#include "net/url_request/url_request_job.h"
-
-static ChromeURLDataManagerBackend* GetBackend(net::URLRequest* request) {
-  return static_cast<ChromeURLRequestContext*>(request->context())->
-      GetChromeURLDataManagerBackend();
-}
-
-// URLRequestChromeJob is a net::URLRequestJob that manages running
-// chrome-internal resource requests asynchronously.
-// It hands off URL requests to ChromeURLDataManager, which asynchronously
-// calls back once the data is available.
-class URLRequestChromeJob : public net::URLRequestJob {
- public:
-  explicit URLRequestChromeJob(net::URLRequest* request);
-
-  // net::URLRequestJob implementation.
-  virtual void Start();
-  virtual void Kill();
-  virtual bool ReadRawData(net::IOBuffer* buf, int buf_size, int *bytes_read);
-  virtual bool GetMimeType(std::string* mime_type) const;
-
-  // Called by ChromeURLDataManager to notify us that the data blob is ready
-  // for us.
-  void DataAvailable(RefCountedMemory* bytes);
-
-  void SetMimeType(const std::string& mime_type) {
-    mime_type_ = mime_type;
-  }
-
- private:
-  virtual ~URLRequestChromeJob();
-
-  // Helper for Start(), to let us start asynchronously.
-  // (This pattern is shared by most net::URLRequestJob implementations.)
-  void StartAsync();
-
-  // Do the actual copy from data_ (the data we're serving) into |buf|.
-  // Separate from ReadRawData so we can handle async I/O.
-  void CompleteRead(net::IOBuffer* buf, int buf_size, int* bytes_read);
-
-  // The actual data we're serving.  NULL until it's been fetched.
-  scoped_refptr<RefCountedMemory> data_;
-  // The current offset into the data that we're handing off to our
-  // callers via the Read interfaces.
-  int data_offset_;
-
-  // For async reads, we keep around a pointer to the buffer that
-  // we're reading into.
-  scoped_refptr<net::IOBuffer> pending_buf_;
-  int pending_buf_size_;
-  std::string mime_type_;
-
-  // The backend is owned by ChromeURLRequestContext and always outlives us.
-  ChromeURLDataManagerBackend* backend_;
-
-  DISALLOW_COPY_AND_ASSIGN(URLRequestChromeJob);
-};
-
-// URLRequestChromeFileJob is a net::URLRequestJob that acts like a file:// URL
-class URLRequestChromeFileJob : public net::URLRequestFileJob {
- public:
-  URLRequestChromeFileJob(net::URLRequest* request, const FilePath& path);
-
- private:
-  virtual ~URLRequestChromeFileJob();
-
-  DISALLOW_COPY_AND_ASSIGN(URLRequestChromeFileJob);
-};
-
-void ChromeURLDataManagerBackend::URLToRequest(const GURL& url,
-                                               std::string* source_name,
-                                               std::string* path) {
-  DCHECK(url.SchemeIs(chrome::kChromeDevToolsScheme) ||
-         url.SchemeIs(chrome::kChromeUIScheme));
-
-  if (!url.is_valid()) {
-    NOTREACHED();
-    return;
-  }
-
-  // Our input looks like: chrome://source_name/extra_bits?foo .
-  // So the url's "host" is our source, and everything after the host is
-  // the path.
-  source_name->assign(url.host());
-
-  const std::string& spec = url.possibly_invalid_spec();
-  const url_parse::Parsed& parsed = url.parsed_for_possibly_invalid_spec();
-  // + 1 to skip the slash at the beginning of the path.
-  int offset = parsed.CountCharactersBefore(url_parse::Parsed::PATH, false) + 1;
-
-  if (offset < static_cast<int>(spec.size()))
-    path->assign(spec.substr(offset));
-}
-
-bool ChromeURLDataManagerBackend::URLToFilePath(const GURL& url,
-                                                FilePath* file_path) {
-  // Parse the URL into a request for a source and path.
-  std::string source_name;
-  std::string relative_path;
-
-  // Remove Query and Ref from URL.
-  GURL stripped_url;
-  GURL::Replacements replacements;
-  replacements.ClearQuery();
-  replacements.ClearRef();
-  stripped_url = url.ReplaceComponents(replacements);
-
-  URLToRequest(stripped_url, &source_name, &relative_path);
-
-  FileSourceMap::const_iterator i(file_sources_.find(source_name));
-  if (i == file_sources_.end())
-    return false;
-
-  // Check that |relative_path| is not an absolute path (otherwise AppendASCII()
-  // will DCHECK). The awkward use of StringType is because on some systems
-  // FilePath expects a std::string, but on others a std::wstring.
-  FilePath p(FilePath::StringType(relative_path.begin(), relative_path.end()));
-  if (p.IsAbsolute())
-    return false;
-
-  *file_path = i->second.AppendASCII(relative_path);
-
-  return true;
-}
-
-ChromeURLDataManagerBackend::ChromeURLDataManagerBackend()
-    : next_request_id_(0) {
-  FilePath inspector_dir;
-  if (PathService::Get(chrome::DIR_INSPECTOR, &inspector_dir))
-    AddFileSource(chrome::kChromeUIDevToolsHost, inspector_dir);
-  AddDataSource(new SharedResourcesDataSource());
-}
-
-ChromeURLDataManagerBackend::~ChromeURLDataManagerBackend() {
-  for (DataSourceMap::iterator i = data_sources_.begin();
-       i != data_sources_.end(); ++i) {
-    i->second->backend_ = NULL;
-  }
-  data_sources_.clear();
-}
-
-// static
-void ChromeURLDataManagerBackend::Register() {
-  net::URLRequest::RegisterProtocolFactory(
-      chrome::kChromeDevToolsScheme,
-      &ChromeURLDataManagerBackend::Factory);
-  net::URLRequest::RegisterProtocolFactory(
-      chrome::kChromeUIScheme,
-      &ChromeURLDataManagerBackend::Factory);
-}
-
-void ChromeURLDataManagerBackend::AddDataSource(
-    ChromeURLDataManager::DataSource* source) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  DataSourceMap::iterator i = data_sources_.find(source->source_name());
-  if (i != data_sources_.end())
-    i->second->backend_ = NULL;
-  data_sources_[source->source_name()] = source;
-  source->backend_ = this;
-}
-
-void ChromeURLDataManagerBackend::AddFileSource(const std::string& source_name,
-                                                const FilePath& file_path) {
-  DCHECK(file_sources_.count(source_name) == 0);
-  file_sources_[source_name] = file_path;
-}
-
-bool ChromeURLDataManagerBackend::HasPendingJob(
-    URLRequestChromeJob* job) const {
-  for (PendingRequestMap::const_iterator i = pending_requests_.begin();
-       i != pending_requests_.end(); ++i) {
-    if (i->second == job)
-      return true;
-  }
-  return false;
-}
-
-bool ChromeURLDataManagerBackend::StartRequest(const GURL& url,
-                                               URLRequestChromeJob* job) {
-  // Parse the URL into a request for a source and path.
-  std::string source_name;
-  std::string path;
-  URLToRequest(url, &source_name, &path);
-
-  // Look up the data source for the request.
-  DataSourceMap::iterator i = data_sources_.find(source_name);
-  if (i == data_sources_.end())
-    return false;
-
-  ChromeURLDataManager::DataSource* source = i->second;
-
-  // Save this request so we know where to send the data.
-  RequestID request_id = next_request_id_++;
-  pending_requests_.insert(std::make_pair(request_id, job));
-
-  // TODO(eroman): would be nicer if the mimetype were set at the same time
-  // as the data blob. For now do it here, since NotifyHeadersComplete() is
-  // going to get called once we return.
-  job->SetMimeType(source->GetMimeType(path));
-
-  ChromeURLRequestContext* context = static_cast<ChromeURLRequestContext*>(
-      job->request()->context());
-
-  // Forward along the request to the data source.
-  MessageLoop* target_message_loop = source->MessageLoopForRequestPath(path);
-  if (!target_message_loop) {
-    // The DataSource is agnostic to which thread StartDataRequest is called
-    // on for this path.  Call directly into it from this thread, the IO
-    // thread.
-    source->StartDataRequest(path, context->is_off_the_record(), request_id);
-  } else {
-    // The DataSource wants StartDataRequest to be called on a specific thread,
-    // usually the UI thread, for this path.
-    target_message_loop->PostTask(
-        FROM_HERE,
-        NewRunnableMethod(source,
-                          &ChromeURLDataManager::DataSource::StartDataRequest,
-                          path, context->is_off_the_record(), request_id));
-  }
-  return true;
-}
-
-void ChromeURLDataManagerBackend::RemoveRequest(URLRequestChromeJob* job) {
-  // Remove the request from our list of pending requests.
-  // If/when the source sends the data that was requested, the data will just
-  // be thrown away.
-  for (PendingRequestMap::iterator i = pending_requests_.begin();
-       i != pending_requests_.end(); ++i) {
-    if (i->second == job) {
-      pending_requests_.erase(i);
-      return;
-    }
-  }
-}
-
-void ChromeURLDataManagerBackend::DataAvailable(RequestID request_id,
-                                                RefCountedMemory* bytes) {
-  // Forward this data on to the pending net::URLRequest, if it exists.
-  PendingRequestMap::iterator i = pending_requests_.find(request_id);
-  if (i != pending_requests_.end()) {
-    // We acquire a reference to the job so that it doesn't disappear under the
-    // feet of any method invoked here (we could trigger a callback).
-    scoped_refptr<URLRequestChromeJob> job(i->second);
-    pending_requests_.erase(i);
-    job->DataAvailable(bytes);
-  }
-}
-
-// static
-net::URLRequestJob* ChromeURLDataManagerBackend::Factory(
-    net::URLRequest* request,
-    const std::string& scheme) {
-  // Try first with a file handler
-  FilePath path;
-  ChromeURLDataManagerBackend* backend = GetBackend(request);
-  if (backend->URLToFilePath(request->url(), &path))
-    return new URLRequestChromeFileJob(request, path);
-
-  // Next check for chrome://view-http-cache/*, which uses its own job type.
-  if (ViewHttpCacheJobFactory::IsSupportedURL(request->url()))
-    return ViewHttpCacheJobFactory::CreateJobForRequest(request);
-
-  // Next check for chrome://appcache-internals/, which uses its own job type.
-  if (ViewAppCacheInternalsJobFactory::IsSupportedURL(request->url()))
-    return ViewAppCacheInternalsJobFactory::CreateJobForRequest(request);
-
-  // Next check for chrome://blob-internals/, which uses its own job type.
-  if (ViewBlobInternalsJobFactory::IsSupportedURL(request->url()))
-    return ViewBlobInternalsJobFactory::CreateJobForRequest(request);
-
-  // Fall back to using a custom handler
-  return new URLRequestChromeJob(request);
-}
-
-URLRequestChromeJob::URLRequestChromeJob(net::URLRequest* request)
-    : net::URLRequestJob(request),
-      data_offset_(0),
-      pending_buf_size_(0),
-      backend_(GetBackend(request)) {
-}
-
-URLRequestChromeJob::~URLRequestChromeJob() {
-  CHECK(!backend_->HasPendingJob(this));
-}
-
-void URLRequestChromeJob::Start() {
-  // Start reading asynchronously so that all error reporting and data
-  // callbacks happen as they would for network requests.
-  MessageLoop::current()->PostTask(FROM_HERE, NewRunnableMethod(
-      this, &URLRequestChromeJob::StartAsync));
-}
-
-void URLRequestChromeJob::Kill() {
-  backend_->RemoveRequest(this);
-}
-
-bool URLRequestChromeJob::GetMimeType(std::string* mime_type) const {
-  *mime_type = mime_type_;
-  return !mime_type_.empty();
-}
-
-void URLRequestChromeJob::DataAvailable(RefCountedMemory* bytes) {
-  if (bytes) {
-    // The request completed, and we have all the data.
-    // Clear any IO pending status.
-    SetStatus(net::URLRequestStatus());
-
-    data_ = bytes;
-    int bytes_read;
-    if (pending_buf_.get()) {
-      CHECK(pending_buf_->data());
-      CompleteRead(pending_buf_, pending_buf_size_, &bytes_read);
-      pending_buf_ = NULL;
-      NotifyReadComplete(bytes_read);
-    }
-  } else {
-    // The request failed.
-    NotifyDone(net::URLRequestStatus(net::URLRequestStatus::FAILED,
-                                     net::ERR_FAILED));
-  }
-}
-
-bool URLRequestChromeJob::ReadRawData(net::IOBuffer* buf, int buf_size,
-                                      int* bytes_read) {
-  if (!data_.get()) {
-    SetStatus(net::URLRequestStatus(net::URLRequestStatus::IO_PENDING, 0));
-    DCHECK(!pending_buf_.get());
-    CHECK(buf->data());
-    pending_buf_ = buf;
-    pending_buf_size_ = buf_size;
-    return false;  // Tell the caller we're still waiting for data.
-  }
-
-  // Otherwise, the data is available.
-  CompleteRead(buf, buf_size, bytes_read);
-  return true;
-}
-
-void URLRequestChromeJob::CompleteRead(net::IOBuffer* buf, int buf_size,
-                                       int* bytes_read) {
-  int remaining = static_cast<int>(data_->size()) - data_offset_;
-  if (buf_size > remaining)
-    buf_size = remaining;
-  if (buf_size > 0) {
-    memcpy(buf->data(), data_->front() + data_offset_, buf_size);
-    data_offset_ += buf_size;
-  }
-  *bytes_read = buf_size;
-}
-
-void URLRequestChromeJob::StartAsync() {
-  if (!request_)
-    return;
-
-  if (backend_->StartRequest(request_->url(), this)) {
-    NotifyHeadersComplete();
-  } else {
-    NotifyStartError(net::URLRequestStatus(net::URLRequestStatus::FAILED,
-                                           net::ERR_INVALID_URL));
-  }
-}
-
-URLRequestChromeFileJob::URLRequestChromeFileJob(net::URLRequest* request,
-                                                 const FilePath& path)
-    : net::URLRequestFileJob(request, path) {
-}
-
-URLRequestChromeFileJob::~URLRequestChromeFileJob() {}
diff --git a/chrome/browser/dom_ui/chrome_url_data_manager_backend.h b/chrome/browser/dom_ui/chrome_url_data_manager_backend.h
deleted file mode 100644
index fe900bc..0000000
--- a/chrome/browser/dom_ui/chrome_url_data_manager_backend.h
+++ /dev/null
@@ -1,99 +0,0 @@
-// Copyright (c) 2011 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.
-
-#ifndef CHROME_BROWSER_DOM_UI_CHROME_URL_DATA_MANAGER_BACKEND_H_
-#define CHROME_BROWSER_DOM_UI_CHROME_URL_DATA_MANAGER_BACKEND_H_
-#pragma once
-
-#include "base/basictypes.h"
-#include "base/ref_counted.h"
-#include "chrome/browser/dom_ui/chrome_url_data_manager.h"
-
-#include <map>
-#include <string>
-#include <vector>
-
-class FilePath;
-class GURL;
-class URLRequestChromeJob;
-
-namespace net {
-class URLRequest;
-class URLRequestJob;
-}
-
-// ChromeURLDataManagerBackend is used internally by ChromeURLDataManager on the
-// IO thread. In most cases you can use the API in ChromeURLDataManager and
-// ignore this class. ChromeURLDataManagerBackend is owned by
-// ChromeURLRequestContext.
-class ChromeURLDataManagerBackend {
- public:
-  typedef int RequestID;
-
-  ChromeURLDataManagerBackend();
-  ~ChromeURLDataManagerBackend();
-
-  // Invoked to register the protocol factories.
-  static void Register();
-
-  // Adds a DataSource to the collection of data sources.
-  void AddDataSource(ChromeURLDataManager::DataSource* source);
-
-  // Add/remove a path from the collection of file sources.
-  // A file source acts like a file:// URL to the specified path.
-  // Calling this from threads other the IO thread must be done via
-  // InvokeLater.
-  void AddFileSource(const std::string& source_name, const FilePath& path);
-
-  // DataSource invokes this. Sends the data to the URLRequest.
-  void DataAvailable(RequestID request_id, RefCountedMemory* bytes);
-
-  static net::URLRequestJob* Factory(net::URLRequest* request,
-                                     const std::string& scheme);
-
- private:
-  friend class URLRequestChromeJob;
-
-  typedef std::map<std::string,
-      scoped_refptr<ChromeURLDataManager::DataSource> > DataSourceMap;
-  typedef std::map<std::string, FilePath> FileSourceMap;
-  typedef std::map<RequestID, URLRequestChromeJob*> PendingRequestMap;
-
-  // Parse a URL into the components used to resolve its request.
-  void URLToRequest(const GURL& url, std::string* source, std::string* path);
-
-  // Translate a chrome resource URL into a local file path if there is one.
-  // Returns false if there is no file handler for this URL
-  bool URLToFilePath(const GURL& url, FilePath* file_path);
-
-  // Called by the job when it's starting up.
-  // Returns false if |url| is not a URL managed by this object.
-  bool StartRequest(const GURL& url, URLRequestChromeJob* job);
-
-  // Remove a request from the list of pending requests.
-  void RemoveRequest(URLRequestChromeJob* job);
-
-  // Returns true if the job exists in |pending_requests_|. False otherwise.
-  // Called by ~URLRequestChromeJob to verify that |pending_requests_| is kept
-  // up to date.
-  bool HasPendingJob(URLRequestChromeJob* job) const;
-
-  // File sources of data, keyed by source name (e.g. "inspector").
-  FileSourceMap file_sources_;
-
-  // Custom sources of data, keyed by source path (e.g. "favicon").
-  DataSourceMap data_sources_;
-
-  // All pending URLRequestChromeJobs, keyed by ID of the request.
-  // URLRequestChromeJob calls into this object when it's constructed and
-  // destructed to ensure that the pointers in this map remain valid.
-  PendingRequestMap pending_requests_;
-
-  // The ID we'll use for the next request we receive.
-  RequestID next_request_id_;
-
-  DISALLOW_COPY_AND_ASSIGN(ChromeURLDataManagerBackend);
-};
-
-#endif  // CHROME_BROWSER_DOM_UI_CHROME_URL_DATA_MANAGER_BACKEND_H_
diff --git a/chrome/browser/dom_ui/conflicts_ui.cc b/chrome/browser/dom_ui/conflicts_ui.cc
index 4e21b29..8631c8d 100644
--- a/chrome/browser/dom_ui/conflicts_ui.cc
+++ b/chrome/browser/dom_ui/conflicts_ui.cc
@@ -14,7 +14,6 @@
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
 #include "chrome/browser/enumerate_modules_model_win.h"
 #include "chrome/browser/metrics/user_metrics.h"
-#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/jstemplate_builder.h"
 #include "chrome/common/notification_observer.h"
@@ -203,7 +202,11 @@ ConflictsUI::ConflictsUI(TabContents* contents) : DOMUI(contents) {
   ConflictsUIHTMLSource* html_source = new ConflictsUIHTMLSource();
 
   // Set up the about:conflicts source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                        &ChromeURLDataManager::AddDataSource,
+                        make_scoped_refptr(html_source)));
 }
 
 // static
diff --git a/chrome/browser/dom_ui/downloads_dom_handler.cc b/chrome/browser/dom_ui/downloads_dom_handler.cc
index 82badc9..c6a22ec 100644
--- a/chrome/browser/dom_ui/downloads_dom_handler.cc
+++ b/chrome/browser/dom_ui/downloads_dom_handler.cc
@@ -22,7 +22,6 @@
 #include "chrome/browser/download/download_item.h"
 #include "chrome/browser/download/download_util.h"
 #include "chrome/browser/metrics/user_metrics.h"
-#include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/jstemplate_builder.h"
 #include "chrome/common/url_constants.h"
@@ -52,8 +51,12 @@ DownloadsDOMHandler::DownloadsDOMHandler(DownloadManager* dlm)
       download_manager_(dlm),
       callback_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)) {
   // Create our fileicon data source.
-  dlm->profile()->GetChromeURLDataManager()->AddDataSource(
-      new FileIconSource());
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(new FileIconSource())));
 }
 
 DownloadsDOMHandler::~DownloadsDOMHandler() {
diff --git a/chrome/browser/dom_ui/downloads_ui.cc b/chrome/browser/dom_ui/downloads_ui.cc
index 2fadd47..63b1b153 100644
--- a/chrome/browser/dom_ui/downloads_ui.cc
+++ b/chrome/browser/dom_ui/downloads_ui.cc
@@ -14,7 +14,6 @@
 #include "chrome/browser/dom_ui/downloads_dom_handler.h"
 #include "chrome/browser/download/download_manager.h"
 #include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/jstemplate_builder.h"
 #include "chrome/common/url_constants.h"
 #include "grit/browser_resources.h"
@@ -135,7 +134,11 @@ DownloadsUI::DownloadsUI(TabContents* contents) : DOMUI(contents) {
   DownloadsUIHTMLSource* html_source = new DownloadsUIHTMLSource();
 
   // Set up the chrome://downloads/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                        &ChromeURLDataManager::AddDataSource,
+                        make_scoped_refptr(html_source)));
 }
 
 // static
diff --git a/chrome/browser/dom_ui/filebrowse_ui.cc b/chrome/browser/dom_ui/filebrowse_ui.cc
index 81dddb2..08dceb3 100644
--- a/chrome/browser/dom_ui/filebrowse_ui.cc
+++ b/chrome/browser/dom_ui/filebrowse_ui.cc
@@ -422,9 +422,13 @@ FilebrowseHandler::~FilebrowseHandler() {
 
 WebUIMessageHandler* FilebrowseHandler::Attach(DOMUI* dom_ui) {
   // Create our favicon data source.
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(new WebUIFavIconSource(dom_ui->GetProfile()))));
   profile_ = dom_ui->GetProfile();
-  profile_->GetChromeURLDataManager()->AddDataSource(
-      new WebUIFavIconSource(profile_));
   tab_contents_ = dom_ui->tab_contents();
   return WebUIMessageHandler::Attach(dom_ui);
 }
@@ -1135,7 +1139,12 @@ FileBrowseUI::FileBrowseUI(TabContents* contents) : HtmlDialogUI(contents) {
   FileBrowseUIHTMLSource* html_source = new FileBrowseUIHTMLSource();
 
   // Set up the chrome://filebrowse/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
 
 // static
diff --git a/chrome/browser/dom_ui/flags_ui.cc b/chrome/browser/dom_ui/flags_ui.cc
index b301673..d57dc3b 100644
--- a/chrome/browser/dom_ui/flags_ui.cc
+++ b/chrome/browser/dom_ui/flags_ui.cc
@@ -14,8 +14,6 @@
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
 #include "chrome/browser/prefs/pref_service.h"
-#include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/jstemplate_builder.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/url_constants.h"
@@ -182,7 +180,11 @@ FlagsUI::FlagsUI(TabContents* contents) : DOMUI(contents) {
   FlagsUIHTMLSource* html_source = new FlagsUIHTMLSource();
 
   // Set up the about:flags source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                        &ChromeURLDataManager::AddDataSource,
+                        make_scoped_refptr(html_source)));
 }
 
 // static
diff --git a/chrome/browser/dom_ui/gpu_internals_ui.cc b/chrome/browser/dom_ui/gpu_internals_ui.cc
index 9948264..c37a071 100644
--- a/chrome/browser/dom_ui/gpu_internals_ui.cc
+++ b/chrome/browser/dom_ui/gpu_internals_ui.cc
@@ -29,8 +29,6 @@
 #include "chrome/browser/net/passive_log_collector.h"
 #include "chrome/browser/net/url_fixer_upper.h"
 #include "chrome/browser/platform_util.h"
-#include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_version_info.h"
 #include "chrome/common/jstemplate_builder.h"
@@ -309,9 +307,9 @@ DictionaryValue* GpuInfoToDict(const GPUInfo& gpu_info) {
   if (gpu_info.level() == GPUInfo::kPartial) {
     info->SetString("level", "partial");
   } else if (gpu_info.level() == GPUInfo::kCompleting) {
-    info->SetString("level", "completing");
+    info->SetString("level", "completing");    
   } else if (gpu_info.level() == GPUInfo::kComplete) {
-    info->SetString("level", "complete");
+    info->SetString("level", "complete");    
   } else {
     DCHECK(false) << "Unrecognized GPUInfo::Level value";
     info->SetString("level", "");
@@ -367,6 +365,11 @@ GpuInternalsUI::GpuInternalsUI(TabContents* contents) : DOMUI(contents) {
   GpuHTMLSource* html_source = new GpuHTMLSource();
 
   // Set up the chrome://gpu/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
 
diff --git a/chrome/browser/dom_ui/history2_ui.cc b/chrome/browser/dom_ui/history2_ui.cc
index aaf7fdc..bdfe536 100644
--- a/chrome/browser/dom_ui/history2_ui.cc
+++ b/chrome/browser/dom_ui/history2_ui.cc
@@ -129,9 +129,12 @@ BrowsingHistoryHandler2::~BrowsingHistoryHandler2() {
 
 WebUIMessageHandler* BrowsingHistoryHandler2::Attach(DOMUI* dom_ui) {
   // Create our favicon data source.
-  Profile* profile = dom_ui->GetProfile();
-  profile->GetChromeURLDataManager()->AddDataSource(
-      new WebUIFavIconSource(profile));
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(new WebUIFavIconSource(dom_ui->GetProfile()))));
 
   // Get notifications when history is cleared.
   registrar_.Add(this, NotificationType::HISTORY_URLS_DELETED,
@@ -397,7 +400,12 @@ HistoryUI2::HistoryUI2(TabContents* contents) : DOMUI(contents) {
   HistoryUIHTMLSource2* html_source = new HistoryUIHTMLSource2();
 
   // Set up the chrome://history2/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
 
 // static
diff --git a/chrome/browser/dom_ui/history_ui.cc b/chrome/browser/dom_ui/history_ui.cc
index 80be7d3..2013256 100644
--- a/chrome/browser/dom_ui/history_ui.cc
+++ b/chrome/browser/dom_ui/history_ui.cc
@@ -129,13 +129,16 @@ BrowsingHistoryHandler::~BrowsingHistoryHandler() {
 
 WebUIMessageHandler* BrowsingHistoryHandler::Attach(DOMUI* dom_ui) {
   // Create our favicon data source.
-  Profile* profile = dom_ui->GetProfile();
-  profile->GetChromeURLDataManager()->AddDataSource(
-      new WebUIFavIconSource(profile));
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(new WebUIFavIconSource(dom_ui->GetProfile()))));
 
   // Get notifications when history is cleared.
   registrar_.Add(this, NotificationType::HISTORY_URLS_DELETED,
-      Source<Profile>(profile->GetOriginalProfile()));
+      Source<Profile>(dom_ui->GetProfile()->GetOriginalProfile()));
   return WebUIMessageHandler::Attach(dom_ui);
 }
 
@@ -385,7 +388,12 @@ HistoryUI::HistoryUI(TabContents* contents) : DOMUI(contents) {
   HistoryUIHTMLSource* html_source = new HistoryUIHTMLSource();
 
   // Set up the chrome://history/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
 
 // static
diff --git a/chrome/browser/dom_ui/keyboard_ui.cc b/chrome/browser/dom_ui/keyboard_ui.cc
index 375acd1..413cb0d 100644
--- a/chrome/browser/dom_ui/keyboard_ui.cc
+++ b/chrome/browser/dom_ui/keyboard_ui.cc
@@ -9,7 +9,6 @@
 #include "base/string_piece.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
-#include "chrome/browser/profiles/profile.h"
 #include "chrome/common/url_constants.h"
 #include "grit/browser_resources.h"
 #include "ui/base/resource/resource_bundle.h"
@@ -20,7 +19,12 @@
 KeyboardUI::KeyboardUI(TabContents* contents)
     : DOMUI(contents) {
   KeyboardHTMLSource* html_source = new KeyboardHTMLSource();
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
 
 KeyboardUI::~KeyboardUI() {
diff --git a/chrome/browser/dom_ui/mediaplayer_ui.cc b/chrome/browser/dom_ui/mediaplayer_ui.cc
index 858d6d8..8b2b300 100644
--- a/chrome/browser/dom_ui/mediaplayer_ui.cc
+++ b/chrome/browser/dom_ui/mediaplayer_ui.cc
@@ -209,9 +209,12 @@ MediaplayerHandler::~MediaplayerHandler() {
 
 WebUIMessageHandler* MediaplayerHandler::Attach(DOMUI* dom_ui) {
   // Create our favicon data source.
-  Profile* profile = dom_ui->GetProfile();
-  profile->GetChromeURLDataManager()->AddDataSource(
-      new WebUIFavIconSource(profile));
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(new WebUIFavIconSource(dom_ui->GetProfile()))));
 
   return WebUIMessageHandler::Attach(dom_ui);
 }
@@ -609,5 +612,10 @@ MediaplayerUI::MediaplayerUI(TabContents* contents) : DOMUI(contents) {
       new MediaplayerUIHTMLSource(is_playlist);
 
   // Set up the chrome://mediaplayer/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
diff --git a/chrome/browser/dom_ui/most_visited_handler.cc b/chrome/browser/dom_ui/most_visited_handler.cc
index 7e9e61e..9bf80c2 100644
--- a/chrome/browser/dom_ui/most_visited_handler.cc
+++ b/chrome/browser/dom_ui/most_visited_handler.cc
@@ -64,21 +64,30 @@ MostVisitedHandler::~MostVisitedHandler() {
 }
 
 WebUIMessageHandler* MostVisitedHandler::Attach(DOMUI* dom_ui) {
-  Profile* profile = dom_ui->GetProfile();
-  url_blacklist_ = profile->GetPrefs()->GetMutableDictionary(
-      prefs::kNTPMostVisitedURLsBlacklist);
-  pinned_urls_ = profile->GetPrefs()->GetMutableDictionary(
-      prefs::kNTPMostVisitedPinnedURLs);
+  url_blacklist_ = dom_ui->GetProfile()->GetPrefs()->
+      GetMutableDictionary(prefs::kNTPMostVisitedURLsBlacklist);
+  pinned_urls_ = dom_ui->GetProfile()->GetPrefs()->
+      GetMutableDictionary(prefs::kNTPMostVisitedPinnedURLs);
   // Set up our sources for thumbnail and favicon data.
-  WebUIThumbnailSource* thumbnail_src = new WebUIThumbnailSource(profile);
-  profile->GetChromeURLDataManager()->AddDataSource(thumbnail_src);
-
-  WebUIFavIconSource* favicon_src = new WebUIFavIconSource(profile);
-  profile->GetChromeURLDataManager()->AddDataSource(favicon_src);
+  WebUIThumbnailSource* thumbnail_src =
+      new WebUIThumbnailSource(dom_ui->GetProfile());
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                        &ChromeURLDataManager::AddDataSource,
+                        make_scoped_refptr(thumbnail_src)));
+
+  WebUIFavIconSource* favicon_src =
+      new WebUIFavIconSource(dom_ui->GetProfile());
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                        &ChromeURLDataManager::AddDataSource,
+                        make_scoped_refptr(favicon_src)));
 
   // Get notifications when history is cleared.
   registrar_.Add(this, NotificationType::HISTORY_URLS_DELETED,
-                 Source<Profile>(profile));
+      Source<Profile>(dom_ui->GetProfile()));
 
   WebUIMessageHandler* result = WebUIMessageHandler::Attach(dom_ui);
 
diff --git a/chrome/browser/dom_ui/net_internals_ui.cc b/chrome/browser/dom_ui/net_internals_ui.cc
index 00e4ce3..8296623 100644
--- a/chrome/browser/dom_ui/net_internals_ui.cc
+++ b/chrome/browser/dom_ui/net_internals_ui.cc
@@ -210,10 +210,10 @@ class NetInternalsMessageHandler::IOThreadImpl
   typedef void (IOThreadImpl::*MessageHandler)(const ListValue*);
 
   // Creates a proxy for |handler| that will live on the IO thread.
-  // |handler| is a weak pointer, since it is possible for the
-  // WebUIMessageHandler to be deleted on the UI thread while we were executing
-  // on the IO thread. |io_thread| is the global IOThread (it is passed in as
-  // an argument since we need to grab it from the UI thread).
+  // |handler| is a weak pointer, since it is possible for the WebUIMessageHandler
+  // to be deleted on the UI thread while we were executing on the IO thread.
+  // |io_thread| is the global IOThread (it is passed in as an argument since
+  // we need to grab it from the UI thread).
   IOThreadImpl(
       const base::WeakPtr<NetInternalsMessageHandler>& handler,
       IOThread* io_thread,
@@ -1162,5 +1162,10 @@ NetInternalsUI::NetInternalsUI(TabContents* contents) : DOMUI(contents) {
   NetInternalsHTMLSource* html_source = new NetInternalsHTMLSource();
 
   // Set up the chrome://net-internals/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
diff --git a/chrome/browser/dom_ui/new_tab_ui.cc b/chrome/browser/dom_ui/new_tab_ui.cc
index d4f6174..ad95bca 100644
--- a/chrome/browser/dom_ui/new_tab_ui.cc
+++ b/chrome/browser/dom_ui/new_tab_ui.cc
@@ -332,7 +332,12 @@ NewTabUI::NewTabUI(TabContents* contents)
   InitializeCSSCaches();
   NewTabHTMLSource* html_source =
       new NewTabHTMLSource(GetProfile()->GetOriginalProfile());
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 
   // Listen for theme installation.
   registrar_.Add(this, NotificationType::BROWSER_THEME_CHANGED,
@@ -417,9 +422,13 @@ void NewTabUI::Observe(NotificationType type,
 }
 
 void NewTabUI::InitializeCSSCaches() {
-  Profile* profile = GetProfile();
-  WebUIThemeSource* theme = new WebUIThemeSource(profile);
-  profile->GetChromeURLDataManager()->AddDataSource(theme);
+  WebUIThemeSource* theme = new WebUIThemeSource(GetProfile());
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(theme)));
 }
 
 // static
diff --git a/chrome/browser/dom_ui/options/browser_options_handler.cc b/chrome/browser/dom_ui/options/browser_options_handler.cc
index b8b1cb5..83d5223 100644
--- a/chrome/browser/dom_ui/options/browser_options_handler.cc
+++ b/chrome/browser/dom_ui/options/browser_options_handler.cc
@@ -126,8 +126,12 @@ void BrowserOptionsHandler::Initialize() {
   Profile* profile = dom_ui_->GetProfile();
 
   // Create our favicon data source.
-  profile->GetChromeURLDataManager()->AddDataSource(
-      new WebUIFavIconSource(profile));
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(new WebUIFavIconSource(profile))));
 
   homepage_.Init(prefs::kHomePage, profile->GetPrefs(), NULL);
   default_browser_policy_.Init(prefs::kDefaultBrowserSettingEnabled,
diff --git a/chrome/browser/dom_ui/options/options_ui.cc b/chrome/browser/dom_ui/options/options_ui.cc
index 24e83d9..2ae3772 100644
--- a/chrome/browser/dom_ui/options/options_ui.cc
+++ b/chrome/browser/dom_ui/options/options_ui.cc
@@ -193,15 +193,25 @@ OptionsUI::OptionsUI(TabContents* contents)
       new OptionsUIHTMLSource(localized_strings);
 
   // Set up the chrome://settings/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 
   // Set up the chrome://theme/ source.
-  WebUIThemeSource* theme = new WebUIThemeSource(contents->profile());
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(theme);
+  WebUIThemeSource* theme = new WebUIThemeSource(GetProfile());
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(theme)));
 
   // Initialize the chrome://about/ source in case the user clicks the credits
   // link.
-  InitializeAboutDataSource(contents->profile());
+  InitializeAboutDataSource();
 }
 
 OptionsUI::~OptionsUI() {
diff --git a/chrome/browser/dom_ui/plugins_ui.cc b/chrome/browser/dom_ui/plugins_ui.cc
index b67397b..74980cb 100644
--- a/chrome/browser/dom_ui/plugins_ui.cc
+++ b/chrome/browser/dom_ui/plugins_ui.cc
@@ -349,7 +349,11 @@ PluginsUI::PluginsUI(TabContents* contents) : DOMUI(contents) {
   PluginsUIHTMLSource* html_source = new PluginsUIHTMLSource();
 
   // Set up the chrome://plugins/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                        &ChromeURLDataManager::AddDataSource,
+                        make_scoped_refptr(html_source)));
 }
 
 
diff --git a/chrome/browser/dom_ui/print_preview_ui.cc b/chrome/browser/dom_ui/print_preview_ui.cc
index a52d173..fd3476c 100644
--- a/chrome/browser/dom_ui/print_preview_ui.cc
+++ b/chrome/browser/dom_ui/print_preview_ui.cc
@@ -8,8 +8,6 @@
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/dom_ui/print_preview_handler.h"
 #include "chrome/browser/dom_ui/print_preview_ui_html_source.h"
-#include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/tab_contents/tab_contents.h"
 
 PrintPreviewUI::PrintPreviewUI(TabContents* contents)
     : DOMUI(contents),
@@ -19,7 +17,12 @@ PrintPreviewUI::PrintPreviewUI(TabContents* contents)
   AddMessageHandler(handler->Attach(this));
 
   // Set up the chrome://print/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source_);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          html_source_));
 }
 
 PrintPreviewUI::~PrintPreviewUI() {
diff --git a/chrome/browser/dom_ui/remoting_ui.cc b/chrome/browser/dom_ui/remoting_ui.cc
index 648b857..f3e0899 100644
--- a/chrome/browser/dom_ui/remoting_ui.cc
+++ b/chrome/browser/dom_ui/remoting_ui.cc
@@ -7,8 +7,6 @@
 #include "base/singleton.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/dom_ui/chrome_url_data_manager.h"
-#include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/url_constants.h"
 #include "grit/theme_resources.h"
 #include "ui/base/resource/resource_bundle.h"
@@ -66,7 +64,11 @@ RemotingUI::RemotingUI(TabContents* contents) : DOMUI(contents) {
   RemotingUIHTMLSource* html_source = new RemotingUIHTMLSource();
 
   // Set up the chrome://remoting source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                        &ChromeURLDataManager::AddDataSource,
+                        make_scoped_refptr(html_source)));
 }
 
 
diff --git a/chrome/browser/dom_ui/shared_resources_data_source.cc b/chrome/browser/dom_ui/shared_resources_data_source.cc
index 167a67a..4922f1e 100644
--- a/chrome/browser/dom_ui/shared_resources_data_source.cc
+++ b/chrome/browser/dom_ui/shared_resources_data_source.cc
@@ -53,6 +53,17 @@ int PathToIDR(const std::string& path) {
 
 }  // namespace
 
+// static
+void SharedResourcesDataSource::Register() {
+  SharedResourcesDataSource* source = new SharedResourcesDataSource();
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(source)));
+}
+
 SharedResourcesDataSource::SharedResourcesDataSource()
     : DataSource(chrome::kChromeUIResourcesHost, NULL) {
 }
diff --git a/chrome/browser/dom_ui/shared_resources_data_source.h b/chrome/browser/dom_ui/shared_resources_data_source.h
index 1aec881..a162b43 100644
--- a/chrome/browser/dom_ui/shared_resources_data_source.h
+++ b/chrome/browser/dom_ui/shared_resources_data_source.h
@@ -18,7 +18,8 @@ class GURL;
 // A DataSource for chrome://resources/ URLs.
 class SharedResourcesDataSource : public ChromeURLDataManager::DataSource {
  public:
-  SharedResourcesDataSource();
+  // Registers an instance of this data source with the ChromeUrlDataManager.
+  static void Register();
 
   // Overridden from ChromeURLDataManager::DataSource:
   virtual void StartDataRequest(const std::string& path,
@@ -27,6 +28,7 @@ class SharedResourcesDataSource : public ChromeURLDataManager::DataSource {
   virtual std::string GetMimeType(const std::string&) const;
 
  private:
+  SharedResourcesDataSource();
   ~SharedResourcesDataSource();
 
   DISALLOW_COPY_AND_ASSIGN(SharedResourcesDataSource);
diff --git a/chrome/browser/dom_ui/slideshow_ui.cc b/chrome/browser/dom_ui/slideshow_ui.cc
index 105fd79..78a3965 100644
--- a/chrome/browser/dom_ui/slideshow_ui.cc
+++ b/chrome/browser/dom_ui/slideshow_ui.cc
@@ -148,10 +148,14 @@ SlideshowHandler::~SlideshowHandler() {
 }
 
 WebUIMessageHandler* SlideshowHandler::Attach(DOMUI* dom_ui) {
-  profile_ = dom_ui->GetProfile();
   // Create our favicon data source.
-  profile_->GetChromeURLDataManager()->AddDataSource(
-      new WebUIFavIconSource(profile_));
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(new WebUIFavIconSource(dom_ui->GetProfile()))));
+  profile_ = dom_ui->GetProfile();
   return WebUIMessageHandler::Attach(dom_ui);
 }
 
@@ -280,5 +284,10 @@ SlideshowUI::SlideshowUI(TabContents* contents) : DOMUI(contents) {
   SlideshowUIHTMLSource* html_source = new SlideshowUIHTMLSource();
 
   // Set up the chrome://slideshow/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
diff --git a/chrome/browser/dom_ui/sync_internals_ui.cc b/chrome/browser/dom_ui/sync_internals_ui.cc
index bf36c5f..0af9f0c 100644
--- a/chrome/browser/dom_ui/sync_internals_ui.cc
+++ b/chrome/browser/dom_ui/sync_internals_ui.cc
@@ -30,8 +30,12 @@ SyncInternalsUI::SyncInternalsUI(TabContents* contents)
   // If this PostTask() call fails, it's most likely because this is
   // being run from a unit test.  The created objects will be cleaned
   // up, anyway.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(
-      new SyncInternalsHTMLSource());
+  (void)BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(new SyncInternalsHTMLSource())));
 }
 
 SyncInternalsUI::~SyncInternalsUI() {
diff --git a/chrome/browser/dom_ui/textfields_ui.cc b/chrome/browser/dom_ui/textfields_ui.cc
index cca22c9..7d75aaa 100644
--- a/chrome/browser/dom_ui/textfields_ui.cc
+++ b/chrome/browser/dom_ui/textfields_ui.cc
@@ -11,8 +11,6 @@
 #include "base/string_piece.h"
 #include "base/values.h"
 #include "chrome/browser/browser_thread.h"
-#include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/tab_contents/tab_contents.h"
 #include "chrome/common/jstemplate_builder.h"
 #include "chrome/common/url_constants.h"
 #include "grit/browser_resources.h"
@@ -70,5 +68,9 @@ TextfieldsUI::TextfieldsUI(TabContents* contents) : DOMUI(contents) {
   TextfieldsUIHTMLSource* html_source = new TextfieldsUIHTMLSource();
 
   // Set up the chrome://textfields/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                        &ChromeURLDataManager::AddDataSource,
+                        make_scoped_refptr(html_source)));
 }
diff --git a/chrome/browser/extensions/extension_function_dispatcher.cc b/chrome/browser/extensions/extension_function_dispatcher.cc
index 3d6f4d4..839b341 100644
--- a/chrome/browser/extensions/extension_function_dispatcher.cc
+++ b/chrome/browser/extensions/extension_function_dispatcher.cc
@@ -391,7 +391,11 @@ ExtensionFunctionDispatcher::ExtensionFunctionDispatcher(
   // ChromeURLDataManager.
   if (extension->HasHostPermission(GURL(chrome::kChromeUIFavIconURL))) {
     WebUIFavIconSource* favicon_source = new WebUIFavIconSource(profile_);
-    profile_->GetChromeURLDataManager()->AddDataSource(favicon_source);
+    BrowserThread::PostTask(
+        BrowserThread::IO, FROM_HERE,
+        NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                          &ChromeURLDataManager::AddDataSource,
+                          make_scoped_refptr(favicon_source)));
   }
 
   // Update the extension permissions. Doing this each time we create an EFD
diff --git a/chrome/browser/extensions/extensions_ui.cc b/chrome/browser/extensions/extensions_ui.cc
index c0406dd..087102c 100644
--- a/chrome/browser/extensions/extensions_ui.cc
+++ b/chrome/browser/extensions/extensions_ui.cc
@@ -959,7 +959,12 @@ ExtensionsUI::ExtensionsUI(TabContents* contents) : DOMUI(contents) {
   ExtensionsUIHTMLSource* html_source = new ExtensionsUIHTMLSource();
 
   // Set up the chrome://extensions/ source.
-  contents->profile()->GetChromeURLDataManager()->AddDataSource(html_source);
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(
+          ChromeURLDataManager::GetInstance(),
+          &ChromeURLDataManager::AddDataSource,
+          make_scoped_refptr(html_source)));
 }
 
 // static
diff --git a/chrome/browser/net/chrome_url_request_context.cc b/chrome/browser/net/chrome_url_request_context.cc
index 573ffdc..e42ae2d 100644
--- a/chrome/browser/net/chrome_url_request_context.cc
+++ b/chrome/browser/net/chrome_url_request_context.cc
@@ -11,7 +11,6 @@
 #include "base/string_util.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_thread.h"
-#include "chrome/browser/dom_ui/chrome_url_data_manager_backend.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/user_script_master.h"
 #include "chrome/browser/io_thread.h"
@@ -733,13 +732,6 @@ ChromeURLRequestContext::ChromeURLRequestContext()
   CheckCurrentlyOnIOThread();
 }
 
-ChromeURLDataManagerBackend*
-    ChromeURLRequestContext::GetChromeURLDataManagerBackend() {
-  if (!chrome_url_data_manager_backend_.get())
-    chrome_url_data_manager_backend_.reset(new ChromeURLDataManagerBackend());
-  return chrome_url_data_manager_backend_.get();
-}
-
 ChromeURLRequestContext::~ChromeURLRequestContext() {
   CheckCurrentlyOnIOThread();
 
diff --git a/chrome/browser/net/chrome_url_request_context.h b/chrome/browser/net/chrome_url_request_context.h
index 943b0fd..5d57b46 100644
--- a/chrome/browser/net/chrome_url_request_context.h
+++ b/chrome/browser/net/chrome_url_request_context.h
@@ -40,7 +40,6 @@ class DnsCertProvenanceChecker;
 class NetworkDelegate;
 }
 
-class ChromeURLDataManagerBackend;
 class ChromeURLRequestContext;
 class ChromeURLRequestContextFactory;
 
@@ -103,8 +102,6 @@ class ChromeURLRequestContext : public net::URLRequestContext {
     return prerender_manager_.get();
   }
 
-  ChromeURLDataManagerBackend* GetChromeURLDataManagerBackend();
-
  protected:
   virtual ~ChromeURLRequestContext();
 
@@ -194,7 +191,6 @@ class ChromeURLRequestContext : public net::URLRequestContext {
   scoped_refptr<ExtensionInfoMap> extension_info_map_;
   scoped_refptr<ExtensionIOEventRouter> extension_io_event_router_;
   scoped_refptr<PrerenderManager> prerender_manager_;
-  scoped_ptr<ChromeURLDataManagerBackend> chrome_url_data_manager_backend_;
 
   bool is_off_the_record_;
 
diff --git a/chrome/browser/printing/cloud_print/cloud_print_setup_flow.cc b/chrome/browser/printing/cloud_print/cloud_print_setup_flow.cc
index 0e2f79d..52e4739 100644
--- a/chrome/browser/printing/cloud_print/cloud_print_setup_flow.cc
+++ b/chrome/browser/printing/cloud_print/cloud_print_setup_flow.cc
@@ -88,8 +88,11 @@ CloudPrintSetupFlow::CloudPrintSetupFlow(const std::string& args,
       delegate_(delegate) {
   // TODO(hclam): The data source should be added once.
   profile_ = profile;
-  profile->GetChromeURLDataManager()->AddDataSource(
-      new CloudPrintSetupSource());
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                        &ChromeURLDataManager::AddDataSource,
+                        make_scoped_refptr(new CloudPrintSetupSource())));
 }
 
 CloudPrintSetupFlow::~CloudPrintSetupFlow() {
diff --git a/chrome/browser/profiles/profile.cc b/chrome/browser/profiles/profile.cc
index 0c59310..85c71ad 100644
--- a/chrome/browser/profiles/profile.cc
+++ b/chrome/browser/profiles/profile.cc
@@ -17,7 +17,6 @@
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/chrome_blob_storage_context.h"
-#include "chrome/browser/dom_ui/chrome_url_data_manager.h"
 #include "chrome/browser/download/download_manager.h"
 #include "chrome/browser/extensions/extension_message_service.h"
 #include "chrome/browser/extensions/extension_pref_store.h"
@@ -631,12 +630,6 @@ class OffTheRecordProfileImpl : public Profile,
     return NULL;
   }
 
-  virtual ChromeURLDataManager* GetChromeURLDataManager() {
-    if (!chrome_url_data_manager_.get())
-      chrome_url_data_manager_.reset(new ChromeURLDataManager(this));
-    return chrome_url_data_manager_.get();
-  }
-
   virtual PromoCounter* GetInstantPromoCounter() {
     return NULL;
   }
@@ -726,8 +719,6 @@ class OffTheRecordProfileImpl : public Profile,
 
   scoped_refptr<PrefProxyConfigTracker> pref_proxy_config_tracker_;
 
-  scoped_ptr<ChromeURLDataManager> chrome_url_data_manager_;
-
   DISALLOW_COPY_AND_ASSIGN(OffTheRecordProfileImpl);
 };
 
diff --git a/chrome/browser/profiles/profile.h b/chrome/browser/profiles/profile.h
index 2f09b1c..976eacd 100644
--- a/chrome/browser/profiles/profile.h
+++ b/chrome/browser/profiles/profile.h
@@ -50,7 +50,7 @@ class BrowserSignin;
 class BrowserThemeProvider;
 class ChromeAppCacheService;
 class ChromeBlobStorageContext;
-class ChromeURLDataManager;
+class ChromeURLRequestContextGetter;
 class CloudPrintProxyService;
 class DesktopNotificationService;
 class DownloadManager;
@@ -497,9 +497,6 @@ class Profile {
   // Gets the policy context associated with this profile.
   virtual policy::ProfilePolicyContext* GetPolicyContext() = 0;
 
-  // Returns the ChromeURLDataManager for this profile.
-  virtual ChromeURLDataManager* GetChromeURLDataManager() = 0;
-
 #if defined(OS_CHROMEOS)
   enum AppLocaleChangedVia {
     // Caused by chrome://settings change.
diff --git a/chrome/browser/profiles/profile_impl.cc b/chrome/browser/profiles/profile_impl.cc
index d3c633d..aa8fabf 100644
--- a/chrome/browser/profiles/profile_impl.cc
+++ b/chrome/browser/profiles/profile_impl.cc
@@ -26,7 +26,6 @@
 #include "chrome/browser/chrome_blob_storage_context.h"
 #include "chrome/browser/content_settings/host_content_settings_map.h"
 #include "chrome/browser/defaults.h"
-#include "chrome/browser/dom_ui/chrome_url_data_manager.h"
 #include "chrome/browser/dom_ui/ntp_resource_cache.h"
 #include "chrome/browser/download/download_manager.h"
 #include "chrome/browser/extensions/default_apps.h"
@@ -1373,12 +1372,6 @@ policy::ProfilePolicyContext* ProfileImpl::GetPolicyContext() {
   return profile_policy_context_.get();
 }
 
-ChromeURLDataManager* ProfileImpl::GetChromeURLDataManager() {
-  if (!chrome_url_data_manager_.get())
-    chrome_url_data_manager_.reset(new ChromeURLDataManager(this));
-  return chrome_url_data_manager_.get();
-}
-
 PromoCounter* ProfileImpl::GetInstantPromoCounter() {
 #if defined(OS_WIN)
   // TODO: enable this when we're ready to turn on the promo.
diff --git a/chrome/browser/profiles/profile_impl.h b/chrome/browser/profiles/profile_impl.h
index d65e7b6..acc0d5b 100644
--- a/chrome/browser/profiles/profile_impl.h
+++ b/chrome/browser/profiles/profile_impl.h
@@ -131,7 +131,6 @@ class ProfileImpl : public Profile,
   virtual PromoCounter* GetInstantPromoCounter();
   virtual BrowserSignin* GetBrowserSignin();
   virtual policy::ProfilePolicyContext* GetPolicyContext();
-  virtual ChromeURLDataManager* GetChromeURLDataManager();
 
 #if defined(OS_CHROMEOS)
   virtual void ChangeAppLocale(const std::string& locale, AppLocaleChangedVia);
@@ -307,8 +306,6 @@ class ProfileImpl : public Profile,
 
   scoped_refptr<PrerenderManager> prerender_manager_;
 
-  scoped_ptr<ChromeURLDataManager> chrome_url_data_manager_;
-
   DISALLOW_COPY_AND_ASSIGN(ProfileImpl);
 };
 
diff --git a/chrome/browser/remoting/setup_flow.cc b/chrome/browser/remoting/setup_flow.cc
index 918855a..2d5811d 100644
--- a/chrome/browser/remoting/setup_flow.cc
+++ b/chrome/browser/remoting/setup_flow.cc
@@ -115,16 +115,18 @@ void SetupFlowDoneStep::DoStart() {
 SetupFlowContext::SetupFlowContext() { }
 SetupFlowContext::~SetupFlowContext() { }
 
-SetupFlow::SetupFlow(const std::string& args,
-                     Profile* profile,
+SetupFlow::SetupFlow(const std::string& args, Profile* profile,
                      SetupFlowStep* first_step)
     : dom_ui_(NULL),
       dialog_start_args_(args),
       profile_(profile),
       current_step_(first_step) {
   // TODO(hclam): The data source should be added once.
-  profile->GetChromeURLDataManager()->AddDataSource(
-      new RemotingResourcesSource());
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                        &ChromeURLDataManager::AddDataSource,
+                        make_scoped_refptr(new RemotingResourcesSource())));
 }
 
 SetupFlow::~SetupFlow() { }
diff --git a/chrome/browser/sync/profile_sync_service_mock.cc b/chrome/browser/sync/profile_sync_service_mock.cc
index 99e9ede..f843159 100644
--- a/chrome/browser/sync/profile_sync_service_mock.cc
+++ b/chrome/browser/sync/profile_sync_service_mock.cc
@@ -9,4 +9,6 @@
 ProfileSyncServiceMock::ProfileSyncServiceMock() {}
 
 ProfileSyncServiceMock::~ProfileSyncServiceMock() {
+  ChromeURLDataManager::GetInstance()->RemoveDataSourceForTest(
+      chrome::kChromeUISyncResourcesHost);
 }
diff --git a/chrome/browser/sync/sync_setup_wizard.cc b/chrome/browser/sync/sync_setup_wizard.cc
index 632d60d..2cb6b7e 100644
--- a/chrome/browser/sync/sync_setup_wizard.cc
+++ b/chrome/browser/sync/sync_setup_wizard.cc
@@ -260,14 +260,19 @@ SyncSetupWizard::SyncSetupWizard(ProfileSyncService* service)
     : service_(service),
       flow_container_(new SyncSetupFlowContainer()),
       parent_window_(NULL) {
-  // If we're in a unit test, we may not have an IO thread or profile.  Avoid
+  // If we're in a unit test, we may not have an IO thread.  Avoid
   // creating a SyncResourcesSource since we may leak it (since it's
   // DeleteOnUIThread).
-  if (BrowserThread::IsMessageLoopValid(BrowserThread::IO) &&
-      service_->profile()) {
+  if (BrowserThread::IsMessageLoopValid(BrowserThread::IO)) {
     // Add our network layer data source for 'cloudy' URLs.
     SyncResourcesSource* sync_source = new SyncResourcesSource();
-    service_->profile()->GetChromeURLDataManager()->AddDataSource(sync_source);
+    bool posted =
+        BrowserThread::PostTask(
+            BrowserThread::IO, FROM_HERE,
+            NewRunnableMethod(ChromeURLDataManager::GetInstance(),
+                              &ChromeURLDataManager::AddDataSource,
+                              make_scoped_refptr(sync_source)));
+    DCHECK(posted);
   }
 }
 
diff --git a/chrome/browser/sync/sync_ui_util_unittest.cc b/chrome/browser/sync/sync_ui_util_unittest.cc
index 96dd2c909..7122170 100644
--- a/chrome/browser/sync/sync_ui_util_unittest.cc
+++ b/chrome/browser/sync/sync_ui_util_unittest.cc
@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 #include "base/basictypes.h"
-#include "chrome/browser/browser_thread.h"
 #include "chrome/browser/sync/sync_ui_util.h"
 #include "chrome/browser/sync/profile_sync_service_mock.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ -13,8 +12,6 @@
 using ::testing::Return;
 using ::testing::NiceMock;
 TEST(SyncUIUtilTest, ConstructAboutInformationWithUnrecoverableErrorTest) {
-  MessageLoopForUI message_loop;
-  BrowserThread ui_thread(BrowserThread::UI, &message_loop);
   NiceMock<ProfileSyncServiceMock> service;
   DictionaryValue strings;
 
diff --git a/chrome/browser/tab_contents/render_view_host_manager_unittest.cc b/chrome/browser/tab_contents/render_view_host_manager_unittest.cc
index 2113459..a2df005 100644
--- a/chrome/browser/tab_contents/render_view_host_manager_unittest.cc
+++ b/chrome/browser/tab_contents/render_view_host_manager_unittest.cc
@@ -275,7 +275,6 @@ TEST_F(RenderViewHostManagerTest, DOMUI) {
 // still swap processes if ShouldSwapProcessesForNavigation is true.
 // Regression test for bug 46290.
 TEST_F(RenderViewHostManagerTest, NonDOMUIChromeURLs) {
-  BrowserThread thread(BrowserThread::UI, &message_loop_);
   SiteInstance* instance = SiteInstance::CreateSiteInstance(profile_.get());
   TestTabContents tab_contents(profile_.get(), instance);
   RenderViewHostManager manager(&tab_contents, &tab_contents);