Rewrite scoped_ptr<T>(NULL) to use the default ctor.

This is a manual cleanup of call sites that invoke scoped_ptr<T>'s
constructor with an explicit NULL argument that are only built on
Android.

BUG=173286
R=rlarocque@chromium.org, yfriedman@chromium.org

Review URL: https://codereview.chromium.org/17780002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@208730 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed