Moved JsonPrefStore to use SequencedWorkerPool

chrome/browser/policy/managed_mode_policy_provider.h

Index: chrome/browser/policy/managed_mode_policy_provider.h
diff --git a/chrome/browser/policy/managed_mode_policy_provider.h b/chrome/browser/policy/managed_mode_policy_provider.h
index ddaaeb754577b4c7cc9173c7bc38b5e77e4a3d69..48f44d26790c7c6dcf551080099f2275e0505cca 100644
--- a/chrome/browser/policy/managed_mode_policy_provider.h
+++ b/chrome/browser/policy/managed_mode_policy_provider.h
@@ -11,6 +11,10 @@
 
 class Profile;
 
+namespace base {
+class SequencedTaskRunner;
+}
+
 namespace policy {
 
 // This class sets policies that are defined by a local user via "Managed Mode".
@@ -25,8 +29,12 @@ class ManagedModePolicyProvider
   static const char kPolicies[];
 
   // Creates a new ManagedModePolicyProvider that caches its policies in a JSON
-  // file inside the profile folder.
-  static ManagedModePolicyProvider* Create(Profile* profile);
+  // file inside the profile folder. |sequenced_task_runner| ensures that all
+  // file I/O operations are executed in the order that does not collide
+  // with Profile's file operations.
+  static ManagedModePolicyProvider* Create(
+      Profile* profile,
+      base::SequencedTaskRunner* sequenced_task_runner);
 
   // Use this constructor to inject a different PrefStore (e.g. for testing).
   explicit ManagedModePolicyProvider(PersistentPrefStore* store);