Delete SkGaussianEdgeShader

No longer used.

Change-Id: I65a61696060ca19f528066ea587e140798450e36
Reviewed-on: https://skia-review.googlesource.com/18132
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
10 files changed