Revert 274647 "Skia roll 1940df9:868074b"

The roll is breaking Windows builders with the following error:

Missing input files:
src\third_party\skia\include\core\SkTileGridPicture.h

> Skia roll 1940df9:868074b
> 
> https://skia.googlesource.com/skia/+log/1940df968da44ef95ddb332270aa23481552ca65..868074b50b0fc3e460d2aa97c1096827fe0a1935
> TBR=jvanverth@google.com
> BUG=
> 
> Review URL: https://codereview.chromium.org/316673002

TBR=skia-deps-roller@chromium.org

Review URL: https://codereview.chromium.org/312803004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@274656 0039d316-1c4b-4281-b951-d872f2087c98

DEPS

@@ -45,7 +45,7 @@ vars = {
   "lss_revision": "26",
   "sfntly_revision": "228",
   "lighttpd_revision": "33737",
-  "skia_revision": "868074b50b0fc3e460d2aa97c1096827fe0a1935",
+  "skia_revision": "1940df968da44ef95ddb332270aa23481552ca65",
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Skia
   # and V8 without interference from each other.