Cleanup the UseSharedProxies preference.

- remove the UserSharedProxies pref from local state
- fix the default value of the pref in the profile pref service
- make the conditionals, when to use or ignore proxy settings, more explicit and clearer.

BUG=258835
TEST=Manually checked all combinations of {DevicePolicy, UserPolicy, SharedNetwork, NotSharedNetwork} x {before, after login} x {enabled, disabled UseSharedProxies} for proxies of the system context, signin profile and user's profile. I checked the proxies by looking at the vlogs and the UI (like net-internals and settings page). I did not test the actual network connectivity of each context.

[email protected], [email protected]

Review URL: https://codereview.chromium.org/18112018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@211954 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index e1818e0f..69c7e85 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -134,11 +134,11 @@
 #include "chrome/browser/chromeos/login/user_image_manager.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #include "chrome/browser/chromeos/login/wallpaper_manager.h"
+#include "chrome/browser/chromeos/net/proxy_config_handler.h"
 #include "chrome/browser/chromeos/policy/auto_enrollment_client.h"
 #include "chrome/browser/chromeos/policy/device_cloud_policy_manager_chromeos.h"
 #include "chrome/browser/chromeos/policy/device_status_collector.h"
 #include "chrome/browser/chromeos/preferences.h"
-#include "chrome/browser/chromeos/proxy_config_service_impl.h"
 #include "chrome/browser/chromeos/settings/device_oauth2_token_service.h"
 #include "chrome/browser/chromeos/settings/device_settings_cache.h"
 #include "chrome/browser/chromeos/status/data_promo_notification.h"
@@ -263,7 +263,6 @@
   chromeos::KioskAppManager::RegisterPrefs(registry);
   chromeos::LoginUtils::RegisterPrefs(registry);
   chromeos::Preferences::RegisterPrefs(registry);
-  chromeos::ProxyConfigServiceImpl::RegisterPrefs(registry);
   chromeos::RegisterDisplayLocalStatePrefs(registry);
   chromeos::ServicesCustomizationDocument::RegisterPrefs(registry);
   chromeos::system::AutomaticRebootManager::RegisterPrefs(registry);
@@ -373,7 +372,7 @@
 #if defined(OS_CHROMEOS)
   chromeos::OAuth2LoginManager::RegisterProfilePrefs(registry);
   chromeos::Preferences::RegisterProfilePrefs(registry);
-  chromeos::ProxyConfigServiceImpl::RegisterProfilePrefs(registry);
+  chromeos::proxy_config::RegisterProfilePrefs(registry);
   extensions::EnterprisePlatformKeysPrivateChallengeUserKeyFunction::
       RegisterProfilePrefs(registry);
   FlagsUI::RegisterProfilePrefs(registry);