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, 3 insertions, 3 deletions

diff --git a/base/trace_event/trace_event_etw_export_win.h b/base/trace_event/trace_event_etw_export_win.h
index c1eafff..7a1c029 100644
--- a/base/trace_event/trace_event_etw_export_win.h
+++ b/base/trace_event/trace_event_etw_export_win.h
@@ -12,11 +12,11 @@
 #include "base/strings/string_piece.h"
 #include "base/trace_event/trace_event_impl.h"
 
-// Fwd.
+namespace base {
+
 template <typename Type>
 struct StaticMemorySingletonTraits;
 
-namespace base {
 namespace trace_event {
 
 class BASE_EXPORT TraceEventETWExport {
@@ -86,7 +86,7 @@ class BASE_EXPORT TraceEventETWExport {
   bool etw_export_enabled_;
 
   // Maps category names to their status (enabled/disabled).
-  std::map<base::StringPiece, bool> categories_status_;
+  std::map<StringPiece, bool> categories_status_;
 
   // Local copy of the ETW keyword.
   uint64 etw_match_any_keyword_;