Reland of [2] of "switch colorfilters to sk_sp (patchset #11 id:200001 of https://codereview.chromium.o…

src/core/SkBlitter.cpp

Index: src/core/SkBlitter.cpp
diff --git a/src/core/SkBlitter.cpp b/src/core/SkBlitter.cpp
index 04897e3828af4ec077ec27102e88b279437969a8..15562168e990a5bbb5eb5fef9b1f1da4c03b8d8e 100644
--- a/src/core/SkBlitter.cpp
+++ b/src/core/SkBlitter.cpp
@@ -844,7 +844,8 @@
     if (SkXfermode::IsMode(mode, SkXfermode::kClear_Mode)) {
         SkPaint* p = paint.writable();
         shader = p->setShader(nullptr);
-        cf = p->setColorFilter(nullptr);
+        p->setColorFilter(nullptr);
+        cf = nullptr;
         mode = p->setXfermodeMode(SkXfermode::kSrc_Mode);
         p->setColor(0);
     }
@@ -867,7 +868,7 @@
 
     if (cf) {
         SkASSERT(shader);
-        paint.writable()->setShader(shader->makeWithColorFilter(cf));
+        paint.writable()->setShader(shader->makeWithColorFilter(sk_ref_sp(cf)));
         shader = paint->getShader();
         // blitters should ignore the presence/absence of a filter, since
         // if there is one, the shader will take care of it.