Let blitters be notified when they're done being used

src/core/SkScan_AntiPath.cpp

Index: src/core/SkScan_AntiPath.cpp
diff --git a/src/core/SkScan_AntiPath.cpp b/src/core/SkScan_AntiPath.cpp
index 0943646ce846c0d1d3f91a12fc320039caa28223..b7d470715de0e9786c9442c20e20999bbd5e3dd7 100644
--- a/src/core/SkScan_AntiPath.cpp
+++ b/src/core/SkScan_AntiPath.cpp
@@ -108,7 +108,6 @@ public:
 
     virtual ~SuperBlitter() {
         this->flush();
-        sk_free(fRunsBuffer);
     }
 
     /// Once fRuns contains a complete supersampled row, flush() blits
@@ -154,7 +153,7 @@ SuperBlitter::SuperBlitter(SkBlitter* realBlitter, const SkIRect& ir,
                            const SkRegion& clip)
         : BaseSuperBlitter(realBlitter, ir, clip) {
     fRunsToBuffer = realBlitter->requestRowsPreserved();
-    fRunsBuffer = sk_malloc_throw(fRunsToBuffer * this->getRunsSz());
+    fRunsBuffer = realBlitter->allocBlitMemory(fRunsToBuffer * this->getRunsSz());
     fCurrentRun = -1;
 
     this->advanceRuns();