clean up (partially) colortable api

Needs this to land: https://codereview.chromium.org/2789853002/

Bug: skia:
Change-Id: I38d916a546b7fa64d000d973e695ddda24a589e7
Reviewed-on: https://skia-review.googlesource.com/10600
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Matt Sarett <msarett@google.com>
diff --git a/samplecode/SampleBlur.cpp b/samplecode/SampleBlur.cpp
index 7e6a325..c43dc9b 100644
--- a/samplecode/SampleBlur.cpp
+++ b/samplecode/SampleBlur.cpp
@@ -4,6 +4,7 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
+
 #include "SampleCode.h"
 #include "SkBlurMask.h"
 #include "SkBlurMaskFilter.h"
@@ -20,12 +21,9 @@
     }
 
     SkBitmap bm;
-    SkColorTable* ctable = new SkColorTable(c, 256);
-
     bm.allocPixels(SkImageInfo::Make(256, 256, kIndex_8_SkColorType,
                                      kPremul_SkAlphaType),
-                   nullptr, ctable);
-    ctable->unref();
+                   SkColorTable::Make(c, 256));
 
     bm.lockPixels();
     const float cx = bm.width() * 0.5f;