Update some uses of Value in chrome/browser to use the base:: namespace.

chrome/browser/chromeos/login/screens/screen_context.cc

Index: chrome/browser/chromeos/login/screens/screen_context.cc
diff --git a/chrome/browser/chromeos/login/screens/screen_context.cc b/chrome/browser/chromeos/login/screens/screen_context.cc
index 91d1cda4b89040cd4e23226ef7e5659535fcb40e..658bd53675b877ce7638fa78a7bad7ec303b772d 100644
--- a/chrome/browser/chromeos/login/screens/screen_context.cc
+++ b/chrome/browser/chromeos/login/screens/screen_context.cc
@@ -87,14 +87,14 @@ bool ScreenContext::HasChanges() const {
   return !changes_.empty();
 }
 
-void ScreenContext::GetChangesAndReset(DictionaryValue* diff) {
+void ScreenContext::GetChangesAndReset(base::DictionaryValue* diff) {
   DCHECK(CalledOnValidThread());
   DCHECK(diff);
   changes_.Swap(diff);
   changes_.Clear();
 }
 
-void ScreenContext::ApplyChanges(const DictionaryValue& diff,
+void ScreenContext::ApplyChanges(const base::DictionaryValue& diff,
                                  std::vector<std::string>* keys) {
   DCHECK(CalledOnValidThread());
   DCHECK(!HasChanges());
@@ -110,12 +110,12 @@ void ScreenContext::ApplyChanges(const DictionaryValue& diff,
   changes_.Clear();
 }
 
-bool ScreenContext::Set(const KeyType& key, Value* value) {
+bool ScreenContext::Set(const KeyType& key, base::Value* value) {
   DCHECK(CalledOnValidThread());
   DCHECK(value);
-  scoped_ptr<Value> new_value(value);
+  scoped_ptr<base::Value> new_value(value);
 
-  Value* current_value;
+  base::Value* current_value;
   bool in_storage = storage_.Get(key, &current_value);
 
   // Don't do anything if |storage_| already contains <|key|, |new_value|> pair.