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/src/effects/gradients/SkTwoPointConicalGradient.cpp b/src/effects/gradients/SkTwoPointConicalGradient.cpp
index 43d6f1f..d9fc39c 100644
--- a/src/effects/gradients/SkTwoPointConicalGradient.cpp
+++ b/src/effects/gradients/SkTwoPointConicalGradient.cpp
@@ -338,9 +338,9 @@
         }
     }
 
-    return SkGradientShader::CreateTwoPointConical(c1, r1, c2, r2, desc.fColors, desc.fPos,
-                                                   desc.fCount, desc.fTileMode, desc.fGradFlags,
-                                                   desc.fLocalMatrix);
+    return SkGradientShader::MakeTwoPointConical(c1, r1, c2, r2, desc.fColors, desc.fPos,
+                                                 desc.fCount, desc.fTileMode, desc.fGradFlags,
+                                                 desc.fLocalMatrix).release();
 }
 
 void SkTwoPointConicalGradient::flatten(SkWriteBuffer& buffer) const {