Make PerTabPrefsTabHelper into PrefsTabHelper, move all prefs code into it.

chrome/browser/prefs/browser_prefs.cc

Index: chrome/browser/prefs/browser_prefs.cc
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index 4fc9091c2717131f1ef1935e2b3e515e230d9cdf..f5616b6b4a18cca51971c955e724b695c8217421 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -51,6 +51,7 @@
 #include "chrome/browser/task_manager/task_manager.h"
 #include "chrome/browser/translate/translate_prefs.h"
 #include "chrome/browser/ui/browser.h"
+#include "chrome/browser/ui/prefs/prefs_tab_helper.h"
 #include "chrome/browser/ui/search_engines/keyword_editor_controller.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
 #include "chrome/browser/ui/webui/flags_ui.h"
@@ -157,6 +158,7 @@ void RegisterUserPrefs(PrefService* user_prefs) {
   DownloadPrefs::RegisterUserPrefs(user_prefs);
   bookmark_utils::RegisterUserPrefs(user_prefs);
   TabContentsWrapper::RegisterUserPrefs(user_prefs);
+  PrefsTabHelper::RegisterUserPrefs(user_prefs);
   TemplateURLPrepopulateData::RegisterUserPrefs(user_prefs);
   ExtensionWebUI::RegisterUserPrefs(user_prefs);
   ExtensionSettingsHandler::RegisterUserPrefs(user_prefs);