Move Singleton and related structs to namespace base

Public APIs from base should live inside base:: so moved Singleton class
and structs to base{} and fixed consumers.

also fixed:

** Presubmit ERRORS **
Found Singleton<T> in the following header files.
Please move them to an appropriate source file so that the template
gets instantiated in a single compilation unit.
  chrome/browser/plugins/plugin_finder.h \
  chromecast/media/base/media_message_loop.h \
  content/browser/media/android/media_drm_credential_manager.h

Presubmit warnings:
src/chrome/browser/extensions/warning_badge_service_factory.h:5:
  #ifndef header guard has wrong style, please use:
  CHROME_BROWSER_EXTENSIONS_WARNING_BADGE_SERVICE_FACTORY_H_
  [build/header_guard] [5]
src/chrome/browser/extensions/warning_badge_service_factory.h:39:
  #endif line should be "#endif  //
  CHROME_BROWSER_EXTENSIONS_WARNING_BADGE_SERVICE_FACTORY_H_"
  [build/header_guard] [5]

TBR=jam@chromium.org

Review URL: https://codereview.chromium.org/1308823002

Cr-Commit-Position: refs/heads/master@{#348136}

1 files changed, 4 insertions, 3 deletions

diff --git a/chrome/browser/apps/app_shim/app_shim_handler_mac.cc b/chrome/browser/apps/app_shim/app_shim_handler_mac.cc
index c7801ad..8b55be1 100644
--- a/chrome/browser/apps/app_shim/app_shim_handler_mac.cc
+++ b/chrome/browser/apps/app_shim/app_shim_handler_mac.cc
@@ -35,8 +35,9 @@ void TerminateIfNoAppWindows() {
 class AppShimHandlerRegistry : public content::NotificationObserver {
  public:
   static AppShimHandlerRegistry* GetInstance() {
-    return Singleton<AppShimHandlerRegistry,
-                     LeakySingletonTraits<AppShimHandlerRegistry> >::get();
+    return base::Singleton<
+        AppShimHandlerRegistry,
+        base::LeakySingletonTraits<AppShimHandlerRegistry>>::get();
   }
 
   AppShimHandler* GetForAppMode(const std::string& app_mode_id) const {
@@ -74,7 +75,7 @@ class AppShimHandlerRegistry : public content::NotificationObserver {
   }
 
  private:
-  friend struct DefaultSingletonTraits<AppShimHandlerRegistry>;
+  friend struct base::DefaultSingletonTraits<AppShimHandlerRegistry>;
   typedef std::map<std::string, AppShimHandler*> HandlerMap;
 
   AppShimHandlerRegistry()