Fixed clusterfuzz issue

BUG=448423

Review URL: https://codereview.chromium.org/881423002
diff --git a/src/core/SkBitmap.cpp b/src/core/SkBitmap.cpp
index c962aea..e77bbbd 100644
--- a/src/core/SkBitmap.cpp
+++ b/src/core/SkBitmap.cpp
@@ -1232,6 +1232,9 @@
 
     SkAutoTUnref<SkPixelRef> pr(SkMallocPixelRef::NewWithData(info, info.minRowBytes(),
                                                               ctable.get(), data.get()));
+    if (!pr.get()) {
+        return false;
+    }
     bitmap->setInfo(pr->info());
     bitmap->setPixelRef(pr, 0, 0);
     return true;