Revert of Rewrite platform headers in public/web/ to public/platform/... (https://codereview.chromium.org/189703002/)

Reason for revert:
Broke Windows, Mac, and ChromeOS build.


Original issue's description:
> Rewrite platform headers in public/web/ to public/platform/...
> 
> Includes of this style are more consistent with the rest of the project and
> easier to verify with DEPS. For consistency, includes in public/web/ of other
> headers in public/web/ are rewritten to list the public/web/ portion as well.
> 
> BUG=350097
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=169597

TBR=abarth@chromium.org,jamesr@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=350097

Review URL: https://codereview.chromium.org/205153006

git-svn-id: svn://svn.chromium.org/blink/trunk@169600 bbb929c8-8fbe-4397-9dbb-9b2b20218538