Implemented types.private.ChromeDirectSetting.onChange

This delta links up the onChange event machinery to the property
change notification machinery.

It follows a pattern established in PreferencesAPI and the
PreferenceEventRouter.
* Given a list of preferences, register event listener added
  observers to each preference.
* On the first added event listener, unregister all observers
  and register all property change listeners.
* On property changes, forward an event to each component
  extension that has a property listener added.

BUG=164227

Review URL: https://chromiumcodereview.appspot.com/18100007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@212307 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 222 insertions, 36 deletions

diff --git a/chrome/browser/extensions/api/preference/chrome_direct_setting.cc b/chrome/browser/extensions/api/preference/chrome_direct_setting.cc
index 161ef9b..6d1bd76 100644
--- a/chrome/browser/extensions/api/preference/chrome_direct_setting.cc
+++ b/chrome/browser/extensions/api/preference/chrome_direct_setting.cc
@@ -5,39 +5,16 @@
 #include "chrome/browser/extensions/api/preference/chrome_direct_setting.h"
 
 #include "base/containers/hash_tables.h"
+#include "base/lazy_instance.h"
 #include "base/prefs/pref_service.h"
 #include "base/values.h"
+#include "chrome/browser/extensions/api/preference/chrome_direct_setting_api.h"
 #include "chrome/browser/extensions/api/preference/preference_api_constants.h"
 #include "chrome/browser/profiles/profile.h"
 
 namespace extensions {
 namespace chromedirectsetting {
 
-namespace {
-
-class PreferenceWhitelist {
- public:
-  PreferenceWhitelist() {
-    whitelist_.insert("googlegeolocationaccess.enabled");
-  }
-
-  ~PreferenceWhitelist() {}
-
-  bool IsPreferenceOnWhitelist(const std::string& pref_key){
-    return whitelist_.find(pref_key) != whitelist_.end();
-  }
-
- private:
-  base::hash_set<std::string> whitelist_;
-
-  DISALLOW_COPY_AND_ASSIGN(PreferenceWhitelist);
-};
-
-static base::LazyInstance<PreferenceWhitelist> preference_whitelist_ =
-    LAZY_INSTANCE_INITIALIZER;
-
-}  // namespace
-
 DirectSettingFunctionBase::DirectSettingFunctionBase() {}
 
 DirectSettingFunctionBase::~DirectSettingFunctionBase() {}
@@ -50,11 +27,6 @@ bool DirectSettingFunctionBase::IsCalledFromComponentExtension() {
   return GetExtension()->location() == Manifest::COMPONENT;
 }
 
-bool DirectSettingFunctionBase::IsPreferenceOnWhitelist(
-    const std::string& pref_key) {
-  return preference_whitelist_.Get().IsPreferenceOnWhitelist(pref_key);
-}
-
 GetDirectSettingFunction::GetDirectSettingFunction() {}
 
 bool GetDirectSettingFunction::RunImpl() {
@@ -62,7 +34,8 @@ bool GetDirectSettingFunction::RunImpl() {
 
   std::string pref_key;
   EXTENSION_FUNCTION_VALIDATE(args_->GetString(0, &pref_key));
-  EXTENSION_FUNCTION_VALIDATE(IsPreferenceOnWhitelist(pref_key));
+  EXTENSION_FUNCTION_VALIDATE(
+    ChromeDirectSettingAPI::Get(profile())->IsPreferenceOnWhitelist(pref_key));
 
   const PrefService::Preference* preference =
       GetPrefService()->FindPreference(pref_key.c_str());
@@ -85,7 +58,8 @@ bool SetDirectSettingFunction::RunImpl() {
 
   std::string pref_key;
   EXTENSION_FUNCTION_VALIDATE(args_->GetString(0, &pref_key));
-  EXTENSION_FUNCTION_VALIDATE(IsPreferenceOnWhitelist(pref_key));
+  EXTENSION_FUNCTION_VALIDATE(
+    ChromeDirectSettingAPI::Get(profile())->IsPreferenceOnWhitelist(pref_key));
 
   DictionaryValue* details = NULL;
   EXTENSION_FUNCTION_VALIDATE(args_->GetDictionary(1, &details));
@@ -115,7 +89,8 @@ bool ClearDirectSettingFunction::RunImpl() {
 
   std::string pref_key;
   EXTENSION_FUNCTION_VALIDATE(args_->GetString(0, &pref_key));
-  EXTENSION_FUNCTION_VALIDATE(IsPreferenceOnWhitelist(pref_key));
+  EXTENSION_FUNCTION_VALIDATE(
+    ChromeDirectSettingAPI::Get(profile())->IsPreferenceOnWhitelist(pref_key));
   GetPrefService()->ClearPref(pref_key.c_str());
 
   return true;
diff --git a/chrome/browser/extensions/api/preference/chrome_direct_setting.h b/chrome/browser/extensions/api/preference/chrome_direct_setting.h
index 1a8164b..7e36344 100644
--- a/chrome/browser/extensions/api/preference/chrome_direct_setting.h
+++ b/chrome/browser/extensions/api/preference/chrome_direct_setting.h
@@ -25,9 +25,6 @@ class DirectSettingFunctionBase : public SyncExtensionFunction {
   // Returns true if the caller is a component extension.
   bool IsCalledFromComponentExtension();
 
-  // Returns true if the preference is on the whitelist.
-  bool IsPreferenceOnWhitelist(const std::string& pref_key);
-
  private:
   DISALLOW_COPY_AND_ASSIGN(DirectSettingFunctionBase);
 };
diff --git a/chrome/browser/extensions/api/preference/chrome_direct_setting_api.cc b/chrome/browser/extensions/api/preference/chrome_direct_setting_api.cc
new file mode 100644
index 0000000..04b4307
--- /dev/null
+++ b/chrome/browser/extensions/api/preference/chrome_direct_setting_api.cc
@@ -0,0 +1,154 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/extensions/api/preference/chrome_direct_setting_api.h"
+
+#include "base/bind.h"
+#include "base/containers/hash_tables.h"
+#include "base/lazy_instance.h"
+#include "base/prefs/pref_change_registrar.h"
+#include "base/prefs/pref_service.h"
+#include "base/strings/stringprintf.h"
+#include "chrome/browser/extensions/api/preference/preference_api_constants.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/profiles/profile.h"
+
+namespace extensions {
+namespace chromedirectsetting {
+
+const char kOnPrefChangeFormat[] =
+    "types.private.ChromeDirectSetting.%s.onChange";
+
+class PreferenceWhitelist {
+ public:
+  PreferenceWhitelist() {
+    whitelist_.insert("googlegeolocationaccess.enabled");
+  }
+
+  ~PreferenceWhitelist() {}
+
+  bool IsPreferenceOnWhitelist(const std::string& pref_key){
+    return whitelist_.find(pref_key) != whitelist_.end();
+  }
+
+  void RegisterEventListeners(
+      Profile* profile,
+      EventRouter::Observer* observer) {
+    for (base::hash_set<std::string>::iterator iter = whitelist_.begin();
+         iter != whitelist_.end();
+         iter++) {
+      std::string event_name = base::StringPrintf(
+          kOnPrefChangeFormat,
+          (*iter).c_str());
+      ExtensionSystem::Get(profile)->event_router()->RegisterObserver(
+          observer,
+          event_name);
+    }
+  }
+
+  void RegisterPropertyListeners(
+      Profile* profile,
+      PrefChangeRegistrar* registrar,
+      const base::Callback<void(const std::string&)>& callback) {
+    for (base::hash_set<std::string>::iterator iter = whitelist_.begin();
+         iter != whitelist_.end();
+         iter++) {
+      const char* pref_key = (*iter).c_str();
+      std::string event_name = base::StringPrintf(
+          kOnPrefChangeFormat,
+          pref_key);
+      registrar->Add(pref_key, callback);
+    }
+  }
+
+ private:
+  base::hash_set<std::string> whitelist_;
+
+  DISALLOW_COPY_AND_ASSIGN(PreferenceWhitelist);
+};
+
+base::LazyInstance<PreferenceWhitelist> preference_whitelist =
+    LAZY_INSTANCE_INITIALIZER;
+
+static base::LazyInstance<ProfileKeyedAPIFactory<ChromeDirectSettingAPI> >
+    g_factory = LAZY_INSTANCE_INITIALIZER;
+
+ChromeDirectSettingAPI::ChromeDirectSettingAPI(Profile* profile)
+    : profile_(profile) {
+  preference_whitelist.Get().RegisterEventListeners(profile, this);
+}
+
+ChromeDirectSettingAPI::~ChromeDirectSettingAPI() {}
+
+// BrowserContextKeyedService implementation.
+void ChromeDirectSettingAPI::Shutdown() {}
+
+// ProfileKeyedAPI implementation.
+ProfileKeyedAPIFactory<ChromeDirectSettingAPI>*
+    ChromeDirectSettingAPI::GetFactoryInstance() {
+  return &g_factory.Get();
+}
+
+// EventRouter::Observer implementation.
+void ChromeDirectSettingAPI::OnListenerAdded(const EventListenerInfo& details) {
+  ExtensionSystem::Get(profile_)->event_router()->UnregisterObserver(this);
+  registrar_.Init(profile_->GetPrefs());
+  preference_whitelist.Get().RegisterPropertyListeners(
+      profile_,
+      &registrar_,
+      base::Bind(&ChromeDirectSettingAPI::OnPrefChanged,
+                 base::Unretained(this),
+                 registrar_.prefs()));
+}
+
+bool ChromeDirectSettingAPI::IsPreferenceOnWhitelist(
+    const std::string& pref_key) {
+  return preference_whitelist.Get().IsPreferenceOnWhitelist(pref_key);
+}
+
+ChromeDirectSettingAPI* ChromeDirectSettingAPI::Get(Profile* profile) {
+  return
+      ProfileKeyedAPIFactory<ChromeDirectSettingAPI>::GetForProfile(profile);
+}
+
+// ProfileKeyedAPI implementation.
+const char* ChromeDirectSettingAPI::service_name() {
+  return "ChromeDirectSettingAPI";
+}
+
+void ChromeDirectSettingAPI::OnPrefChanged(
+    PrefService* pref_service, const std::string& pref_key) {
+  std::string event_name = base::StringPrintf(kOnPrefChangeFormat,
+                                              pref_key.c_str());
+  EventRouter* router = ExtensionSystem::Get(profile_)->event_router();
+  if (router && router->HasEventListener(event_name)) {
+    const PrefService::Preference* preference =
+        profile_->GetPrefs()->FindPreference(pref_key.c_str());
+    const base::Value* value = preference->GetValue();
+
+    scoped_ptr<DictionaryValue> result(new DictionaryValue);
+    result->Set(preference_api_constants::kValue, value->DeepCopy());
+    base::ListValue args;
+    args.Append(result.release());
+
+    ExtensionService* extension_service =
+        ExtensionSystem::Get(profile_)->extension_service();
+    const ExtensionSet* extensions = extension_service->extensions();
+    for (ExtensionSet::const_iterator it = extensions->begin();
+         it != extensions->end(); ++it) {
+      if ((*it)->location() == Manifest::COMPONENT) {
+        std::string extension_id = (*it)->id();
+        if (router->ExtensionHasEventListener(extension_id, event_name)) {
+          scoped_ptr<base::ListValue> args_copy(args.DeepCopy());
+          scoped_ptr<Event> event(new Event(event_name, args_copy.Pass()));
+          router->DispatchEventToExtension(extension_id, event.Pass());
+        }
+      }
+    }
+  }
+}
+
+}  // namespace chromedirectsetting
+}  // namespace extensions
+
diff --git a/chrome/browser/extensions/api/preference/chrome_direct_setting_api.h b/chrome/browser/extensions/api/preference/chrome_direct_setting_api.h
new file mode 100644
index 0000000..0fd6207
--- /dev/null
+++ b/chrome/browser/extensions/api/preference/chrome_direct_setting_api.h
@@ -0,0 +1,60 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_API_PREFERENCE_CHROME_DIRECT_SETTING_API_H__
+#define CHROME_BROWSER_EXTENSIONS_API_PREFERENCE_CHROME_DIRECT_SETTING_API_H__
+
+#include "chrome/browser/extensions/api/profile_keyed_api_factory.h"
+#include "chrome/browser/extensions/event_router.h"
+
+class PrefChangeRegistrar;
+class Profile;
+
+namespace extensions {
+namespace chromedirectsetting {
+
+class ChromeDirectSettingAPI : public ProfileKeyedAPI,
+                               public EventRouter::Observer {
+ public:
+  explicit ChromeDirectSettingAPI(Profile* profile);
+
+  virtual ~ChromeDirectSettingAPI();
+
+  // BrowserContextKeyedService implementation.
+  virtual void Shutdown() OVERRIDE;
+
+  // ProfileKeyedAPI implementation.
+  static ProfileKeyedAPIFactory<ChromeDirectSettingAPI>* GetFactoryInstance();
+
+  // EventRouter::Observer implementation.
+  virtual void OnListenerAdded(const EventListenerInfo& details) OVERRIDE;
+
+  // Returns true if the preference is on the whitelist.
+  bool IsPreferenceOnWhitelist(const std::string& pref_key);
+
+  // Convenience method to get the ChromeDirectSettingAPI for a profile.
+  static ChromeDirectSettingAPI* Get(Profile* profile);
+
+ private:
+  friend class ProfileKeyedAPIFactory<ChromeDirectSettingAPI>;
+
+  // ProfileKeyedAPI implementation.
+  static const char* service_name();
+
+  void OnPrefChanged(PrefService* pref_service, const std::string& pref_key);
+
+  static const bool kServiceIsNULLWhileTesting = true;
+  static const bool kServiceRedirectedInIncognito = false;
+
+  PrefChangeRegistrar registrar_;
+  Profile* profile_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChromeDirectSettingAPI);
+};
+
+}  // namespace chromedirectsetting
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_PREFERENCE_CHROME_DIRECT_SETTING_API_H__
+