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/SampleHairModes.cpp b/samplecode/SampleHairModes.cpp
index ae41aa9..085581c 100644
--- a/samplecode/SampleHairModes.cpp
+++ b/samplecode/SampleHairModes.cpp
@@ -60,7 +60,7 @@
     return H;
 }
 
-static SkShader* make_bg_shader() {
+static sk_sp<SkShader> make_bg_shader() {
     SkBitmap bm;
     bm.allocN32Pixels(2, 2);
     *bm.getAddr32(0, 0) = *bm.getAddr32(1, 1) = 0xFFFFFFFF;
@@ -69,17 +69,15 @@
     SkMatrix m;
     m.setScale(SkIntToScalar(6), SkIntToScalar(6));
 
-    return SkShader::CreateBitmapShader(bm,
-                                        SkShader::kRepeat_TileMode,
-                                        SkShader::kRepeat_TileMode,
-                                        &m);
+    return SkShader::MakeBitmapShader(bm, SkShader::kRepeat_TileMode,
+                                      SkShader::kRepeat_TileMode, &m);
 }
 
 class HairModesView : public SampleView {
     SkPaint fBGPaint;
 public:
     HairModesView() {
-        fBGPaint.setShader(make_bg_shader())->unref();
+        fBGPaint.setShader(make_bg_shader());
     }
 
 protected: