use Make instead of Create to return a shared shader

src/core/SkPaint.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPaint.h"
 #include "SkAutoKern.h"
 #include "SkChecksum.h"
@@ skipping 1911 matching lines @@
     this->setTextEncoding(static_cast<TextEncoding>((tmp >> 0) & 0xFF));
 
     if (flatFlags & kHasTypeface_FlatFlag) {
         this->setTypeface(buffer.readTypeface());
     } else {
         this->setTypeface(nullptr);
     }
 
     if (flatFlags & kHasEffects_FlatFlag) {
         SkSafeUnref(this->setPathEffect(buffer.readPathEffect()));
-        SkSafeUnref(this->setShader(buffer.readShader()));
+        this->setShader(buffer.readShader());
         SkSafeUnref(this->setXfermode(buffer.readXfermode()));
         SkSafeUnref(this->setMaskFilter(buffer.readMaskFilter()));
         SkSafeUnref(this->setColorFilter(buffer.readColorFilter()));
         SkSafeUnref(this->setRasterizer(buffer.readRasterizer()));
         SkSafeUnref(this->setLooper(buffer.readDrawLooper()));
         SkSafeUnref(this->setImageFilter(buffer.readImageFilter()));
 
         if (buffer.isVersionLT(SkReadBuffer::kAnnotationsMovedToCanvas_Version)) {
             // We used to store annotations here (string+skdata) if this bool was true
             if (buffer.readBool()) {
@@ skipping 415 matching lines @@
 }
 
 uint32_t SkPaint::getHash() const {
     // We're going to hash 10 pointers and 7 32-bit values, finishing up with fBitfields,
     // so fBitfields should be 10 pointers and 6 32-bit values from the start.
     static_assert(offsetof(SkPaint, fBitfields) == 9 * sizeof(void*) + 6 * sizeof(uint32_t),
                   "SkPaint_notPackedTightly");
     return SkChecksum::Murmur3(reinterpret_cast<const uint32_t*>(this),
                                offsetof(SkPaint, fBitfields) + sizeof(fBitfields));
 }