Introduce //components/user_prefs, use to eliminate c/b/prefs dependency in Autofill.

chrome/browser/profiles/profile.cc

Index: chrome/browser/profiles/profile.cc
diff --git a/chrome/browser/profiles/profile.cc b/chrome/browser/profiles/profile.cc
index 0302bf875d437f6ceda8c39dab9a17f89340d8d5..fac7caba40df8e3a2aa98cc98dbc3c24c732fc73 100644
--- a/chrome/browser/profiles/profile.cc
+++ b/chrome/browser/profiles/profile.cc
@@ -8,11 +8,13 @@
 
 #include "base/prefs/pref_service.h"
 #include "build/build_config.h"
-#include "chrome/browser/prefs/pref_registry_syncable.h"
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/sync_prefs.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/pref_names.h"
+#include "components/user_prefs/pref_registry_syncable.h"
+#include "components/user_prefs/user_prefs.h"
+#include "components/user_prefs/user_prefs_delegate.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/web_contents.h"
@@ -23,10 +25,40 @@
 #include "chrome/common/chrome_switches.h"
 #endif
 
+namespace {
+
+// Used to initialize the UserPrefs component.
+class ChromeUserPrefsDelegate : public components::UserPrefsDelegate {
+ public:
+  ChromeUserPrefsDelegate() {}
+  virtual ~ChromeUserPrefsDelegate() {}
+
+  virtual PrefService* PrefServiceFromBrowserContext(
+      content::BrowserContext* context) OVERRIDE {
+    return static_cast<Profile*>(context)->GetPrefs();
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ChromeUserPrefsDelegate);
+};
+
+}  // namespace
+
 Profile::Profile()
     : restored_last_session_(false),
       sent_destroyed_notification_(false),
       accessibility_pause_level_(0) {
+  // One-time initialization of UserPrefs. This is the safest to do
+  // it, since there can be no PrefService for user preferences unless
+  // there is a Profile, and even test code will create a Profile
+  // object if it uses a Profile at all, although it may bypass
+  // e.g. BrowserProcess or ProfileManager or
+  // chrome_prefs::CreateProfilePrefs.
+  components::UserPrefs* user_prefs = components::UserPrefs::GetInstance();

[Elliot Glaysher, 2013/02/28 21:58:57]

You mentioned ContetnClient. If this is supposed to be a single, global
singleton, putting this in the startup code (ChromeMainDelegate or one of its
ExtraParts) would make more sense.

Putting it here doesn't make it feel like this is startup code, but something
user configurable since Profile isn't the only consumer of BrowserContexts.

+  if (!user_prefs->IsInitialized()) {
+    user_prefs->Initialize(scoped_ptr<components::UserPrefsDelegate>(
+        new ChromeUserPrefsDelegate).Pass());
+  }
 }
 
 // static