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, 1 deletions

diff --git a/chrome/browser/extensions/extension_assets_manager_chromeos.h b/chrome/browser/extensions/extension_assets_manager_chromeos.h
index bfb37ad..670a144 100644
--- a/chrome/browser/extensions/extension_assets_manager_chromeos.h
+++ b/chrome/browser/extensions/extension_assets_manager_chromeos.h
@@ -9,7 +9,10 @@
 
 #include "chrome/browser/extensions/extension_assets_manager.h"
 
+namespace base {
 template <typename T> struct DefaultSingletonTraits;
+}
+
 class PrefRegistrySimple;
 
 namespace base {
@@ -64,7 +67,7 @@ class ExtensionAssetsManagerChromeOS : public ExtensionAssetsManager {
   static void SetSharedInstallDirForTesting(const base::FilePath& install_dir);
 
  private:
-  friend struct DefaultSingletonTraits<ExtensionAssetsManagerChromeOS>;
+  friend struct base::DefaultSingletonTraits<ExtensionAssetsManagerChromeOS>;
 
   ExtensionAssetsManagerChromeOS();
   ~ExtensionAssetsManagerChromeOS() override;