Orphan ProcXfermode, with an eye towards removing it

tests/PaintTest.cpp

Index: tests/PaintTest.cpp
diff --git a/tests/PaintTest.cpp b/tests/PaintTest.cpp
index f6aede1200c5a2db57f6eb10a2301364160bc4e3..914e61e4b033ad47cab077277e7e538d0c1ec851 100644
--- a/tests/PaintTest.cpp
+++ b/tests/PaintTest.cpp
@@ -325,7 +325,7 @@ DEF_TEST(Paint_FlatteningTraits, r) {
 
     SkWriteBuffer writer;
     SkPaint::FlatteningTraits::Flatten(writer, paint);
-    const size_t expectedBytesWritten = sizeof(void*) == 8 ? 40 : 32;
+    const size_t expectedBytesWritten = sizeof(void*) == 8 ? 32 : 24;
     ASSERT(expectedBytesWritten == writer.bytesWritten());
 
     const uint32_t* written = writer.getWriter32()->contiguousArray();