Clean up pref change notification handling.

chrome/browser/extensions/extension_management_browsertest.cc

Index: chrome/browser/extensions/extension_management_browsertest.cc
diff --git a/chrome/browser/extensions/extension_management_browsertest.cc b/chrome/browser/extensions/extension_management_browsertest.cc
index ffde5930a3aecda865f56c49bc78a4a64fa77ec4..1e8b11fe4dcb5e2e7de0a4a7cd2d385b82c5768b 100644
--- a/chrome/browser/extensions/extension_management_browsertest.cc
+++ b/chrome/browser/extensions/extension_management_browsertest.cc
@@ -11,6 +11,7 @@
 #include "chrome/browser/extensions/extension_updater.h"
 #include "chrome/browser/prefs/pref_notifier.h"
 #include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/prefs/scoped_pref_update.h"
 #include "chrome/browser/profile.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/ui/browser.h"
@@ -337,14 +338,16 @@ IN_PROC_BROWSER_TEST_F(ExtensionManagementTest, ExternalPolicyRefresh) {
   ASSERT_TRUE(service->disabled_extensions()->empty());
 
   // Set the policy as a user preference and fire notification observers.
-  PrefService* prefs = browser()->profile()->GetPrefs();
-  ListValue* forcelist =
-      prefs->GetMutableList(prefs::kExtensionInstallForceList);
-  ASSERT_TRUE(forcelist->empty());
-  forcelist->Append(Value::CreateStringValue(
-      "ogjcoiohnmldgjemafoockdghcjciccf;"
-      "http://localhost/autoupdate/manifest"));
-  prefs->pref_notifier()->FireObservers(prefs::kExtensionInstallForceList);
+  {
+    PrefService* prefs = browser()->profile()->GetPrefs();
+    ScopedPrefUpdate pref_update(prefs, prefs::kExtensionInstallForceList);
+    ListValue* forcelist =
+        prefs->GetMutableList(prefs::kExtensionInstallForceList);
+    ASSERT_TRUE(forcelist->empty());
+    forcelist->Append(Value::CreateStringValue(
+        "ogjcoiohnmldgjemafoockdghcjciccf;"
+        "http://localhost/autoupdate/manifest"));
+  }
 
   // Check if the extension got installed.
   ASSERT_TRUE(WaitForExtensionInstall());