Update base/scoped_ptr.h from system_wrappers/interface/scoped_ptr.h
Update base/scoped_ptr.h from system_wrappers/interface/scoped_ptr.h

The latter file was more up-to-date. The files are now identical
with the following exceptions:

  * The namespace used (rtc vs. webrtc).

  * The name of the include guard.

  * base/scoped_ptr.h still has two extra methods, accept() and use().

  * base/scoped_ptr.h still includes webrtc/base/common.h even though
    it doesn't need it itself, since several .cc files expect to get
    it for free by incuding base/scoped_ptr.h. This is of course bad
    manners, and the "unused" include will be removed in a future CL.

A later CL will remove system_wrappers/interface/scoped_ptr.h.

R=andrew@webrtc.org

Committed: https://code.google.com/p/webrtc/source/detail?r=8147
And reverted again, because out-of-tree code using this file was defining nullptr to 0: https://code.google.com/p/webrtc/source/detail?r=8149

Review URL: https://webrtc-codereview.appspot.com/36919004

Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#8196}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 73ca1945eccf8e52d2a237a6ef7d3352a4d11d4d

sippet/webrtc,sippet/webrtc,sippet/webrtc,sippet/webrtc,sippet/webrtc,sippet/webrtc