Introduce incognito preference settings.

chrome/browser/prefs/pref_service.cc

Index: chrome/browser/prefs/pref_service.cc
diff --git a/chrome/browser/prefs/pref_service.cc b/chrome/browser/prefs/pref_service.cc
index 4a3110c5c801990e3b5a76d547a588a2cfa62885..be4e37897c4d2f639a875738ce080aaed7636b7f 100644
--- a/chrome/browser/prefs/pref_service.cc
+++ b/chrome/browser/prefs/pref_service.cc
@@ -21,9 +21,11 @@
 #include "base/utf_string_conversions.h"
 #include "build/build_config.h"
 #include "chrome/browser/browser_thread.h"
+#include "chrome/browser/extensions/extension_pref_store.h"
 #include "chrome/browser/policy/configuration_policy_pref_store.h"
 #include "chrome/browser/prefs/command_line_pref_store.h"
 #include "chrome/browser/prefs/default_pref_store.h"
+#include "chrome/browser/prefs/overlay_persistent_pref_store.h"
 #include "chrome/browser/prefs/pref_notifier_impl.h"
 #include "chrome/browser/prefs/pref_value_store.h"
 #include "chrome/browser/profiles/profile.h"
@@ -115,9 +117,26 @@ PrefService* PrefService::CreatePrefService(const FilePath& pref_filename,
       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE));
   ConfigurationPolicyPrefStore* recommended =
       ConfigurationPolicyPrefStore::CreateRecommendedPolicyPrefStore();
+  DefaultPrefStore* default_pref_store = new DefaultPrefStore();
 
   return new PrefService(managed, device_management, extension_prefs,
-                         command_line, user, recommended, profile);
+                         command_line, user, recommended, default_pref_store,
+                         profile, true);
+}
+
+PrefService* PrefService::CreateIncognitoPrefService(
+    PrefStore* incognito_extension_prefs) {
+  return new PrefService(
+      managed_platform_prefs_,
+      device_management_prefs_,
+      incognito_extension_prefs,
+      command_line_prefs_,
+      new OverlayPersistentPrefStore(user_pref_store_.get()),
+      recommended_prefs_,
+      default_store_,
+      profile_,
+      false
+  );
 }
 
 PrefService::PrefService(PrefStore* managed_platform_prefs,
@@ -126,21 +145,30 @@ PrefService::PrefService(PrefStore* managed_platform_prefs,
                          PrefStore* command_line_prefs,
                          PersistentPrefStore* user_prefs,
                          PrefStore* recommended_prefs,
-                         Profile* profile)
-    : user_pref_store_(user_prefs) {
+                         DefaultPrefStore* default_store,
+                         Profile* profile,
+                         bool init_from_storage)
+    : managed_platform_prefs_(managed_platform_prefs),
+      device_management_prefs_(device_management_prefs),
+      extension_prefs_(extension_prefs),
+      command_line_prefs_(command_line_prefs),
+      recommended_prefs_(recommended_prefs),
+      user_pref_store_(user_prefs),
+      default_store_(default_store),
+      profile_(profile){
   pref_notifier_.reset(new PrefNotifierImpl(this));
-  default_store_ = new DefaultPrefStore();
   pref_value_store_ =
-      new PrefValueStore(managed_platform_prefs,
-                         device_management_prefs,
-                         extension_prefs,
-                         command_line_prefs,
+      new PrefValueStore(managed_platform_prefs_,
+                         device_management_prefs_,
+                         extension_prefs_,
+                         command_line_prefs_,
                          user_pref_store_,
-                         recommended_prefs,
+                         recommended_prefs_,
                          default_store_,
                          pref_notifier_.get(),
-                         profile);
-  InitFromStorage();
+                         profile_);
+  if (init_from_storage)
+    InitFromStorage();
 }
 
 PrefService::~PrefService() {
@@ -328,15 +356,23 @@ FilePath PrefService::GetFilePath(const char* path) const {
 }
 
 bool PrefService::HasPrefPath(const char* path) const {
-  return pref_value_store_->HasPrefPath(path);
+  const Preference* pref = FindPreference(path);
+  return pref && !pref->IsDefaultValue();
 }
 
 const PrefService::Preference* PrefService::FindPreference(
     const char* pref_name) const {
   DCHECK(CalledOnValidThread());
-  Preference p(this, pref_name);
+  Preference p(this, pref_name, Value::TYPE_NULL);
   PreferenceSet::const_iterator it = prefs_.find(&p);
-  return it == prefs_.end() ? NULL : *it;
+  if (it != prefs_.end())
+    return *it;
+  const Value::ValueType type = default_store_->GetType(pref_name);
+  if (type == Value::TYPE_NULL)
+    return NULL;
+  Preference* new_pref = new Preference(this, pref_name, type);
+  prefs_.insert(new_pref);
+  return new_pref;
 }
 
 bool PrefService::ReadOnly() const {
@@ -349,10 +385,7 @@ PrefNotifier* PrefService::pref_notifier() const {
 
 bool PrefService::IsManagedPreference(const char* pref_name) const {
   const Preference* pref = FindPreference(pref_name);
-  if (pref && pref->IsManaged()) {
-    return true;
-  }
-  return false;
+  return pref && pref->IsManaged();
 }
 
 const DictionaryValue* PrefService::GetDictionary(const char* path) const {
@@ -408,18 +441,10 @@ void PrefService::RegisterPreference(const char* path, Value* default_value) {
   DCHECK(orig_type != Value::TYPE_NULL && orig_type != Value::TYPE_BINARY) <<
          "invalid preference type: " << orig_type;
 
-  // We set the default value of dictionaries and lists to be null so it's
-  // easier for callers to check for empty dict/list prefs. The PrefValueStore
-  // accepts ownership of the value (null or default_value).
-  if (Value::TYPE_LIST == orig_type || Value::TYPE_DICTIONARY == orig_type) {
-    default_store_->SetDefaultValue(path, Value::CreateNullValue());
-  } else {
-    // Hand off ownership.
-    default_store_->SetDefaultValue(path, scoped_value.release());
-  }
+  // Hand off ownership.
+  default_store_->SetDefaultValue(path, scoped_value.release());
 
-  pref_value_store_->RegisterPreferenceType(path, orig_type);
-  prefs_.insert(new Preference(this, path));
+  prefs_.insert(new Preference(this, path, orig_type));
 }
 
 void PrefService::ClearPref(const char* path) {
@@ -442,13 +467,7 @@ void PrefService::Set(const char* path, const Value& value) {
     return;
   }
 
-  // Allow dictionary and list types to be set to null, which removes their
-  // user values.
-  if (value.GetType() == Value::TYPE_NULL &&
-      (pref->GetType() == Value::TYPE_DICTIONARY ||
-       pref->GetType() == Value::TYPE_LIST)) {
-    user_pref_store_->RemoveValue(path);
-  } else if (pref->GetType() != value.GetType()) {
+  if (pref->GetType() != value.GetType()) {
     NOTREACHED() << "Trying to set pref " << path
                  << " of type " << pref->GetType()
                  << " to value of type " << value.GetType();
@@ -590,15 +609,17 @@ void PrefService::SetUserPrefValue(const char* path, Value* new_value) {
 // PrefService::Preference
 
 PrefService::Preference::Preference(const PrefService* service,
-                                    const char* name)
+                                    const char* name,
+                                    Value::ValueType type)
       : name_(name),
+        type_(type),
         pref_service_(service) {
   DCHECK(name);
   DCHECK(service);
 }
 
 Value::ValueType PrefService::Preference::GetType() const {
-  return pref_service_->pref_value_store_->GetRegisteredType(name_);
+  return type_;
 }
 
 const Value* PrefService::Preference::GetValue() const {
@@ -606,8 +627,10 @@ const Value* PrefService::Preference::GetValue() const {
       "Must register pref before getting its value";
 
   Value* found_value = NULL;
-  if (pref_service_->pref_value_store_->GetValue(name_, &found_value))
+  if (pref_service_->pref_value_store_->GetValue(name_, type_, &found_value)) {
+    DCHECK(found_value->IsType(type_));
     return found_value;
+  }
 
   // Every registered preference has at least a default value.
   NOTREACHED() << "no valid value found for registered pref " << name_;