GM: some header cleanup

gm.h includes sk_tool_utils.h but does not use it.

The bulk of this CL makes each gm that uses sk_tool_utils include it.

sk_tool_utils.h also provided SkRandom and SkTDArray,
so a couple GMs add those headers too.

Change-Id: Ieb2a7c542f0ca89c3223f744fc11b0ff37af36c1
Reviewed-on: https://skia-review.googlesource.com/10014
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Herb Derby <herb@google.com>
diff --git a/gm/morphology.cpp b/gm/morphology.cpp
index f60079b..d1513c4 100644
--- a/gm/morphology.cpp
+++ b/gm/morphology.cpp
@@ -6,6 +6,7 @@
  */
 
 #include "gm.h"
+#include "sk_tool_utils.h"
 #include "SkMorphologyImageFilter.h"
 
 #define WIDTH 700