Add array bounds assertion and improve type conversion for empty strings.

BUG=324829
R=abarth@chromium.org

Review URL: https://codereview.chromium.org/105133002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238751 0039d316-1c4b-4281-b951-d872f2087c98
Re-enable GN in the GYP build.

This fixes Android GYP defines by more conservatively rewriting all key
characters that aren't alphabetic.

BUG=321352
R=thakis@chromium.org

Review URL: https://codereview.chromium.org/102243005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238752 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238751
SVN changes up to revision 238752