Reland: Remove SkLights include from SkCanvas.h

SkLights.h pulls in a bunch of other headers and is not needed (fwdecl
works fine).

Change-Id: I3ed97cd7861e51dcb7cfa7950a97b420dbc6fbfb
TBR=reed@google.com
Reviewed-on: https://skia-review.googlesource.com/15143
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Florin Malita <fmalita@chromium.org>
45 files changed