Allow running gyp_to_android without SkUserConfig.

The old code requires that include/config/SkUserConfig.h exists,
to ensure that it gets copied into Android's
include/core/SkUserConfig.h when we do a merge. However, if a
developer wants to make changes and rerun the script, they
should not have to recreate include/config/SkUserConfig.h just
to rerun the script. By default, allow the original to not
exist and just skip the copy.

Update tests to pass. Also add tests to support this use case.

Make gyp_to_android.py executable.

R=robertphillips@google.com, halcanary@google.com

Author: scroggo@google.com

Review URL: https://codereview.chromium.org/242203008

git-svn-id: http://skia.googlecode.com/svn/trunk@14273 2bbb7eff-a529-9590-31e7-b0007b416f81
4 files changed