Make members of Singleton<T> private and only visible to the singleton type. This enforces that the Singleton<T> pattern can only be used within classes which want singleton-ness.

As part of this CL I have also fixed up files which got missed in my previous CLs to use a GetInstance() method and use Singleton<T> from the source file.

There are a small number of places where I have also switched to LazyInstance as that was more appropriate for types used in a single source file.

BUG=65298
TEST=all existing tests should continue to pass.

Review URL: http://codereview.chromium.org/5682008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@68932 0039d316-1c4b-4281-b951-d872f2087c98

9 files changed, 36 insertions, 20 deletions

diff --git a/chrome/browser/chromeos/browser_main_chromeos.cc b/chrome/browser/chromeos/browser_main_chromeos.cc
index df4653a..776a82b 100644
--- a/chrome/browser/chromeos/browser_main_chromeos.cc
+++ b/chrome/browser/chromeos/browser_main_chromeos.cc
@@ -4,8 +4,8 @@
 
 #include "chrome/browser/chromeos/browser_main_chromeos.h"
 
+#include "base/lazy_instance.h"
 #include "base/message_loop.h"
-#include "base/singleton.h"
 
 #include <gtk/gtk.h>
 
@@ -38,12 +38,13 @@ class MessageLoopObserver : public MessageLoopForUI::Observer {
   }
 };
 
-void BrowserMainPartsChromeos::PostMainMessageLoopStart() {
-  static Singleton<MessageLoopObserver> observer;
+static base::LazyInstance<MessageLoopObserver> g_message_loop_observer(
+    base::LINKER_INITIALIZED);
 
+void BrowserMainPartsChromeos::PostMainMessageLoopStart() {
   BrowserMainPartsPosix::PostMainMessageLoopStart();
   MessageLoopForUI* message_loop = MessageLoopForUI::current();
-  message_loop->AddObserver(observer.get());
+  message_loop->AddObserver(g_message_loop_observer.Pointer());
 }
 
 // static
diff --git a/chrome/browser/chromeos/login/screen_locker.cc b/chrome/browser/chromeos/login/screen_locker.cc
index f59307b..2167650 100644
--- a/chrome/browser/chromeos/login/screen_locker.cc
+++ b/chrome/browser/chromeos/login/screen_locker.cc
@@ -16,9 +16,9 @@
 #include "app/resource_bundle.h"
 #include "app/x11_util.h"
 #include "base/command_line.h"
+#include "base/lazy_instance.h"
 #include "base/metrics/histogram.h"
 #include "base/message_loop.h"
-#include "base/singleton.h"
 #include "base/string_util.h"
 #include "base/timer.h"
 #include "base/utf_string_conversions.h"
@@ -194,6 +194,9 @@ class ScreenLockObserver : public chromeos::ScreenLockLibrary::Observer,
   DISALLOW_COPY_AND_ASSIGN(ScreenLockObserver);
 };
 
+static base::LazyInstance<ScreenLockObserver> g_screen_lock_observer(
+    base::LINKER_INITIALIZED);
+
 // A ScreenLock window that covers entire screen to keep the keyboard
 // focus/events inside the grab widget.
 class LockWindow : public views::WidgetGtk {
@@ -901,7 +904,7 @@ void ScreenLocker::UnlockScreenFailed() {
 
 // static
 void ScreenLocker::InitClass() {
-  Singleton<ScreenLockObserver>::get();
+  g_screen_lock_observer.Get();
 }
 
 ////////////////////////////////////////////////////////////////////////////////
diff --git a/chrome/browser/chromeos/login/signed_settings_helper.cc b/chrome/browser/chromeos/login/signed_settings_helper.cc
index ad86e83..6a1a735 100644
--- a/chrome/browser/chromeos/login/signed_settings_helper.cc
+++ b/chrome/browser/chromeos/login/signed_settings_helper.cc
@@ -7,9 +7,9 @@
 #include <string>
 #include <vector>
 
+#include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/ref_counted.h"
-#include "base/singleton.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/chromeos/login/signed_settings.h"
 
@@ -262,10 +262,13 @@ class SignedSettingsHelperImpl : public SignedSettingsHelper,
 
   std::vector<OpContext*> pending_contexts_;
 
-  friend struct DefaultSingletonTraits<SignedSettingsHelperImpl>;
+  friend struct base::DefaultLazyInstanceTraits<SignedSettingsHelperImpl>;
   DISALLOW_COPY_AND_ASSIGN(SignedSettingsHelperImpl);
 };
 
+static base::LazyInstance<SignedSettingsHelperImpl>
+    g_signed_settings_helper_impl(base::LINKER_INITIALIZED);
+
 SignedSettingsHelperImpl::SignedSettingsHelperImpl() {
 }
 
@@ -371,7 +374,7 @@ void SignedSettingsHelperImpl::OnOpCompleted(OpContext* context) {
 }
 
 SignedSettingsHelper* SignedSettingsHelper::Get() {
-  return Singleton<SignedSettingsHelperImpl>::get();
+  return g_signed_settings_helper_impl.Pointer();
 }
 
 }  // namespace chromeos
diff --git a/chrome/browser/chromeos/offline/offline_load_service.cc b/chrome/browser/chromeos/offline/offline_load_service.cc
index 08f2362..ace85d8 100644
--- a/chrome/browser/chromeos/offline/offline_load_service.cc
+++ b/chrome/browser/chromeos/offline/offline_load_service.cc
@@ -4,8 +4,8 @@
 
 #include "chrome/browser/chromeos/offline/offline_load_service.h"
 
+#include "base/lazy_instance.h"
 #include "base/ref_counted.h"
-#include "base/singleton.h"
 #include "chrome/browser/browser_thread.h"
 #include "chrome/browser/tab_contents/navigation_controller.h"
 #include "chrome/browser/tab_contents/tab_contents.h"
@@ -24,7 +24,7 @@ class OfflineLoadServiceSingleton {
   }
 
  private:
-  friend struct DefaultSingletonTraits<OfflineLoadServiceSingleton>;
+  friend struct base::DefaultLazyInstanceTraits<OfflineLoadServiceSingleton>;
   OfflineLoadServiceSingleton()
       : offline_load_service_(new chromeos::OfflineLoadService()) {}
   virtual ~OfflineLoadServiceSingleton() {}
@@ -34,9 +34,12 @@ class OfflineLoadServiceSingleton {
   DISALLOW_COPY_AND_ASSIGN(OfflineLoadServiceSingleton);
 };
 
+static base::LazyInstance<OfflineLoadServiceSingleton>
+    g_offline_load_service_singleton(base::LINKER_INITIALIZED);
+
 // static
 OfflineLoadService* OfflineLoadService::Get() {
-  return Singleton<OfflineLoadServiceSingleton>::get()->offline_load_service();
+  return g_offline_load_service_singleton.Get().offline_load_service();
 }
 
 void OfflineLoadService::Observe(NotificationType type,
diff --git a/chrome/browser/enumerate_modules_model_win.cc b/chrome/browser/enumerate_modules_model_win.cc
index b521b6c..cff39c6 100644
--- a/chrome/browser/enumerate_modules_model_win.cc
+++ b/chrome/browser/enumerate_modules_model_win.cc
@@ -672,6 +672,11 @@ string16 ModuleEnumerator::GetSubjectNameFromDigitalSignature(
 
 //  ----------------------------------------------------------------------------
 
+// static
+EnumerateModulesModel* EnumerateModulesModel::GetSingleton() {
+  return Singleton<EnumerateModulesModel>::get();
+}
+
 void EnumerateModulesModel::ScanNow() {
   if (scanning_)
     return;  // A scan is already in progress.
diff --git a/chrome/browser/enumerate_modules_model_win.h b/chrome/browser/enumerate_modules_model_win.h
index 9000a6c..15492a5 100644
--- a/chrome/browser/enumerate_modules_model_win.h
+++ b/chrome/browser/enumerate_modules_model_win.h
@@ -218,9 +218,7 @@ class ModuleEnumerator : public base::RefCountedThreadSafe<ModuleEnumerator> {
 // notification.
 class EnumerateModulesModel {
  public:
-  static EnumerateModulesModel* GetSingleton() {
-    return Singleton<EnumerateModulesModel>::get();
-  }
+  static EnumerateModulesModel* GetSingleton();
 
   // Returns the number of suspected bad modules found in the last scan.
   // Returns 0 if no scan has taken place yet.
diff --git a/chrome/browser/gtk/browser_toolbar_gtk.cc b/chrome/browser/gtk/browser_toolbar_gtk.cc
index ad10e51..d3dffff 100644
--- a/chrome/browser/gtk/browser_toolbar_gtk.cc
+++ b/chrome/browser/gtk/browser_toolbar_gtk.cc
@@ -626,7 +626,7 @@ bool BrowserToolbarGtk::ShouldOnlyShowLocation() const {
 
 gboolean BrowserToolbarGtk::OnWrenchMenuButtonExpose(GtkWidget* sender,
                                                      GdkEventExpose* expose) {
-  if (!Singleton<UpgradeDetector>::get()->notify_upgrade())
+  if (!UpgradeDetector::GetInstance()->notify_upgrade())
     return FALSE;
 
   const SkBitmap& badge =
diff --git a/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc b/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
index 7ec0303..2bc0a49 100644
--- a/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
+++ b/chrome/browser/safe_browsing/safe_browsing_blocking_page.cc
@@ -76,6 +76,9 @@ static const char* const kTakeMeBackCommand = "takeMeBack";
 // static
 SafeBrowsingBlockingPageFactory* SafeBrowsingBlockingPage::factory_ = NULL;
 
+static base::LazyInstance<SafeBrowsingBlockingPage::UnsafeResourceMap>
+    g_unsafe_resource_map(base::LINKER_INITIALIZED);
+
 // The default SafeBrowsingBlockingPageFactory.  Global, made a singleton so we
 // don't leak it.
 class SafeBrowsingBlockingPageFactoryImpl
@@ -559,7 +562,7 @@ void SafeBrowsingBlockingPage::NotifySafeBrowsingService(
 // static
 SafeBrowsingBlockingPage::UnsafeResourceMap*
     SafeBrowsingBlockingPage::GetUnsafeResourcesMap() {
-  return Singleton<UnsafeResourceMap>::get();
+  return g_unsafe_resource_map.Pointer();
 }
 
 // static
diff --git a/chrome/browser/safe_browsing/safe_browsing_blocking_page.h b/chrome/browser/safe_browsing/safe_browsing_blocking_page.h
index 53b21a0..cfe2358 100644
--- a/chrome/browser/safe_browsing/safe_browsing_blocking_page.h
+++ b/chrome/browser/safe_browsing/safe_browsing_blocking_page.h
@@ -44,6 +44,9 @@ class TabContents;
 
 class SafeBrowsingBlockingPage : public InterstitialPage {
  public:
+  typedef std::vector<SafeBrowsingService::UnsafeResource> UnsafeResourceList;
+  typedef std::map<TabContents*, UnsafeResourceList> UnsafeResourceMap;
+
   virtual ~SafeBrowsingBlockingPage();
 
   // Shows a blocking page warning the user about phishing/malware for a
@@ -66,8 +69,6 @@ class SafeBrowsingBlockingPage : public InterstitialPage {
   virtual void Proceed();
   virtual void DontProceed();
 
-  typedef std::vector<SafeBrowsingService::UnsafeResource> UnsafeResourceList;
-
  protected:
   friend class SafeBrowsingBlockingPageTest;
 
@@ -118,7 +119,6 @@ class SafeBrowsingBlockingPage : public InterstitialPage {
   // A list of SafeBrowsingService::UnsafeResource for a tab that the user
   // should be warned about.  They are queued when displaying more than one
   // interstitial at a time.
-  typedef std::map<TabContents*, UnsafeResourceList> UnsafeResourceMap;
   static UnsafeResourceMap* GetUnsafeResourcesMap();
 
   // Notifies the SafeBrowsingService on the IO thread whether to proceed or not