Revert 289312 "Move StringToUpperASCII and LowerCaseEqualsASCII ..."

> Move StringToUpperASCII and LowerCaseEqualsASCII to the base namespace
> 
> Convert LowerCaseEqualsASCII to take StringPiece. In the current patch this is
> generally a NOP but will allow me to delete the other 4 variants in a followup
> (wanted to do that separately since that will require more review, since
> callsites will be changed in nontrivial ways).
> 
> In some cases, LowerCaseEqualsASCII is called with a WebString, which no
> longer is implicitly converted. I added base::string16(...) around such
> calls to force the right conversion. It happened in these files:
>   window_container_type.cc
>   savable_resources.cc
>   render_view_impl.cc
>   blink_ax_tree_source.cc
>   password_form_conversion_utils.cc
>   translate_helper.cc
>   chrome_render_view_observer.cc
>   dom_serializer_browsertest.cc
> 
> R=jamesr@chromium.org
> 
> Review URL: https://codereview.chromium.org/448143008

TBR=brettw@chromium.org

Review URL: https://codereview.chromium.org/474483002

git-svn-id: http://src.chromium.org/svn/trunk/src/base@289320 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
Move file_util to base/files/ directory.

This updates the includes in base but leaves a forwarding header for the rest of the project for now.

R=yzshen@chromium.org

Review URL: https://codereview.chromium.org/468253002

git-svn-id: http://src.chromium.org/svn/trunk/src/base@289360 4ff67af0-8c30-449e-8e8b-ad334ec8d88c