Add scoped_ptr-safe base::Value to Dictionary/List conversion functions.

base/values.cc

Index: base/values.cc
diff --git a/base/values.cc b/base/values.cc
index c829a7f2f884f30d6aa76477dff94cbf76ecd708..9b2483e7c18c538e877f8563118b633a4433507f 100644
--- a/base/values.cc
+++ b/base/values.cc
@@ -351,6 +351,16 @@ bool BinaryValue::Equals(const Value* other) const {
 
 ///////////////////// DictionaryValue ////////////////////
 
+// static
+scoped_ptr<DictionaryValue> DictionaryValue::From(scoped_ptr<Value> value) {
+  DictionaryValue* out;
+  if (value && value->GetAsDictionary(&out)) {
+    ignore_result(value.release());
+    return make_scoped_ptr(out);
+  }
+  return nullptr;
+}
+
 DictionaryValue::DictionaryValue()
     : Value(TYPE_DICTIONARY) {
 }
@@ -870,6 +880,16 @@ bool DictionaryValue::Equals(const Value* other) const {
 
 ///////////////////// ListValue ////////////////////
 
+// static
+scoped_ptr<ListValue> ListValue::From(scoped_ptr<Value> value) {
+  ListValue* out;
+  if (value && value->GetAsList(&out)) {
+    ignore_result(value.release());
+    return make_scoped_ptr(out);
+  }
+  return nullptr;
+}
+
 ListValue::ListValue() : Value(TYPE_LIST) {
 }