s/sk_tools::DrawCheckerboard/sk_tool_utils::draw_checkerboard/

BUG=skia:

Review URL: https://codereview.chromium.org/873333004
diff --git a/samplecode/SampleColorFilter.cpp b/samplecode/SampleColorFilter.cpp
index 175f724..af1cd93 100644
--- a/samplecode/SampleColorFilter.cpp
+++ b/samplecode/SampleColorFilter.cpp
@@ -5,7 +5,7 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
-#include "Checkerboard.h"
+#include "sk_tool_utils.h"
 #include "SampleCode.h"
 #include "SkView.h"
 #include "SkCanvas.h"
@@ -118,7 +118,7 @@
 public:
     ColorFilterView() {
         fBitmap = createBitmap(N);
-        fShader = sk_tools::CreateCheckerboardShader(
+        fShader = sk_tool_utils::create_checkerboard_shader(
                 0xFFCCCCCC, 0xFFFFFFFF, 12);
 
         if (false) { // avoid bit rot, suppress warning
diff --git a/samplecode/SampleFatBits.cpp b/samplecode/SampleFatBits.cpp
index 9da3513..dfe5ba0 100644
--- a/samplecode/SampleFatBits.cpp
+++ b/samplecode/SampleFatBits.cpp
@@ -5,7 +5,7 @@
  * found in the LICENSE file.
  */
 
-#include "Checkerboard.h"
+#include "sk_tool_utils.h"
 #include "SampleCode.h"
 #include "SkView.h"
 #include "SkCanvas.h"
@@ -87,7 +87,7 @@
         fBounds.set(0, 0, SkIntToScalar(width * zoom), SkIntToScalar(height * zoom));
         fMatrix.setScale(SkIntToScalar(zoom), SkIntToScalar(zoom));
         fInverse.setScale(SK_Scalar1 / zoom, SK_Scalar1 / zoom);
-        fShader.reset(sk_tools::CreateCheckerboardShader(
+        fShader.reset(sk_tool_utils::create_checkerboard_shader(
                               0xFFCCCCCC, 0xFFFFFFFF, zoom));
 
         SkImageInfo info = SkImageInfo::MakeN32Premul(width, height);
diff --git a/samplecode/SampleUnpremul.cpp b/samplecode/SampleUnpremul.cpp
index 889d067..7e5c950 100644
--- a/samplecode/SampleUnpremul.cpp
+++ b/samplecode/SampleUnpremul.cpp
@@ -7,7 +7,7 @@
 
 #include "gm.h"
 
-#include "Checkerboard.h"
+#include "sk_tool_utils.h"
 #include "Resources.h"
 #include "SampleCode.h"
 #include "SkBlurMask.h"
@@ -76,7 +76,7 @@
     }
 
     void onDrawBackground(SkCanvas* canvas) SK_OVERRIDE {
-        sk_tools::DrawCheckerboard(canvas, 0xFFCCCCCC, 0xFFFFFFFF, 12);
+        sk_tool_utils::draw_checkerboard(canvas, 0xFFCCCCCC, 0xFFFFFFFF, 12);
     }
 
     void onDrawContent(SkCanvas* canvas) SK_OVERRIDE {