include what you use

BUG=skia:

Change-Id: I3b9fb3db06a26c55f338f05418ca8ba6fbe7cedf
Reviewed-on: https://skia-review.googlesource.com/8400
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>

gm/clipdrawdraw.cpp

@@ -6,6 +6,7 @@
  */
 
 #include "gm.h"
+#include "SkRegion.h"
 
 // This GM exercises the use case found in crbug.com/423834.
 // The following pattern:

include/core/SkCanvas.h

@@ -17,9 +17,6 @@
 #include "SkLights.h"
 #include "../private/SkShadowParams.h"
 
-// remove this as soon as clients do their own IWYU
-#include "SkRegion.h"
-
 class GrContext;
 class GrRenderTargetContext;
 class SkBaseDevice;