Convert PrefSyncStatus into PrefRegistrationFlags

base/prefs/pref_registry.h

Index: base/prefs/pref_registry.h
diff --git a/base/prefs/pref_registry.h b/base/prefs/pref_registry.h
index a500b6e691a08e73a0be65651da892edaf86aec7..f27929c6936a8049420d77ff99a20d3aee1e62a6 100644
--- a/base/prefs/pref_registry.h
+++ b/base/prefs/pref_registry.h
@@ -27,10 +27,28 @@ class PrefStore;
 // also work, but this is being deprecated.
 class BASE_PREFS_EXPORT PrefRegistry : public base::RefCounted<PrefRegistry> {
  public:
+  // Registration flags that can be specified which impact how the pref will
+  // behave or be stored. This will be passed in a bitmask when the pref is
+  // registered. Subclasses of PrefRegistry can specify their own flags. Care
+  // must be taken to ensure none of these overlap with the flags below.
+  enum PrefRegistrationFlags {
+    // No flags are specified.
+    NO_REGISTRATION_FLAGS = 0,
+
+    // The first 8 bits are reserved for subclasses of PrefRegistry to use.
+  };
+
   typedef PrefValueMap::const_iterator const_iterator;
+  typedef std::map<std::string, uint32> PrefRegistrationFlagsMap;
 
   PrefRegistry();
 
+  // Retrieve the set of registration flags for preferences currently
+  // registered.
+  const PrefRegistrationFlagsMap& registration_flags() const {

[Mattias Nissler (ping if slow), 2015/04/22 07:06:34]

OK, so you made the change to not store entries if flags == 0. Please also
replace this function with a GetRegistrationFlags(const std::string& pref)
function that returns the correct flags value regardless of whether the pref has
an entry in |registration_flags_|.

[raymes, 2015/04/23 05:21:03]

Done.

+    return registration_flags_;
+  }
+
   // Gets the registered defaults.
   scoped_refptr<PrefStore> defaults();
 
@@ -47,11 +65,17 @@ class BASE_PREFS_EXPORT PrefRegistry : public base::RefCounted<PrefRegistry> {
   friend class base::RefCounted<PrefRegistry>;
   virtual ~PrefRegistry();
 
-  // Used by subclasses to register a default value for a preference.
-  void RegisterPreference(const std::string& path, base::Value* default_value);
+  // Used by subclasses to register a default value and registration flags for
+  // a preference. |flags| is a bitmask of |PrefRegistrationFlags|.
+  void RegisterPreference(const std::string& path,
+                          base::Value* default_value,
+                          uint32 flags);
 
   scoped_refptr<DefaultPrefStore> defaults_;
 
+  // A map of pref name to a bitmask of PrefRegistrationFlags.
+  PrefRegistrationFlagsMap registration_flags_;
+
  private:
   DISALLOW_COPY_AND_ASSIGN(PrefRegistry);
 };