use Make instead of Create to return a shared shader

Partially updated call sites. Undefine the flag in SkSHader.h to convert the remaining sites.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1772463002

Review URL: https://codereview.chromium.org/1772463002
diff --git a/samplecode/SampleRegion.cpp b/samplecode/SampleRegion.cpp
index eb3e134..639203b 100644
--- a/samplecode/SampleRegion.cpp
+++ b/samplecode/SampleRegion.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 "SkView.h"
 #include "SkCanvas.h"
@@ -78,10 +79,8 @@
     // of our pts[] array.
     const SkScalar pos[] = { 0, 0.9f, SK_Scalar1 };
 
-    SkShader* s = SkGradientShader::CreateLinear(pts, colors, pos, 3,
-                                                 SkShader::kClamp_TileMode);
     SkPaint p;
-    p.setShader(s)->unref();
+    p.setShader(SkGradientShader::MakeLinear(pts, colors, pos, 3, SkShader::kClamp_TileMode));
     p.setXfermodeMode(SkXfermode::kDstIn_Mode);
     canvas->drawRect(bounds, p);
 
@@ -105,10 +104,9 @@
     const SkPoint pts[] = { { x, y }, { x + paint.measureText(str, len), y } };
     const SkColor colors[] = { SK_ColorBLACK, SK_ColorBLACK, 0 };
     const SkScalar pos[] = { 0, 0.9f, 1 };
-    SkShader* s = SkGradientShader::CreateLinear(pts, colors, pos,
+    paint.setShader(SkGradientShader::MakeLinear(pts, colors, pos,
                                                  SK_ARRAY_COUNT(colors),
-                                                 SkShader::kClamp_TileMode);
-    paint.setShader(s)->unref();
+                                                 SkShader::kClamp_TileMode));
     canvas->drawText(str, len, x, y, paint);
 
     y += 20;