Revert of IWYU: 'core' target, files starting A-C. (patchset #5 id:80001 of https://codereview.chromium.org/1265033002/ )

Reason for revert:
revert to unblock DEPS roll

../../chrome/browser/chromeos/display/overscan_calibrator.cc:43:10: error: variable has incomplete type 'SkPath'
  SkPath base_path;

Original issue's description:
> IWYU: 'core' target, files starting A-C.
>
> TBR=reed@google.com
> Verbal lgtm, does not change API.
>
> Committed: https://skia.googlesource.com/skia/+/7403d87db8e43d4c2b5b25ac22a0ebc22bd09d69

TBR=reed@google.com,mtklein@google.com,bungeman@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1273613002
diff --git a/gm/shadows.cpp b/gm/shadows.cpp
index 82b5fd9..729104c 100644
--- a/gm/shadows.cpp
+++ b/gm/shadows.cpp
@@ -1,14 +1,13 @@
+
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
-
 #include "gm.h"
-#include "SkBlurDrawLooper.h"
 #include "SkBlurMask.h"
-#include "SkPath.h"
+#include "SkBlurDrawLooper.h"
 
 namespace skiagm {