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}


CrOS-Libchrome-Original-Commit: 36aa8be4eb53b3ea75b84a9646e0204725f3bc43
12 files changed
tree: 009cc94c74ebe3fe33b8d15084a0e0c1922b02b9
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/