Remove public_headers.gypi, unneeded by Skia.

This file not needed by Skia, and is almost always out of date.
We recommend generating this inside Android WebView, where it is
used. Generating it is relatively straightforward; here is one way:
https://codereview.chromium.org/198063002/diff/110001/platform_tools/android/gyp_gen/gen_public_headers.py

BUG=skia:2350
R=robertphillips@google.com

Author: scroggo@google.com

Review URL: https://codereview.chromium.org/381633003
1 file changed