Add libFuzzer style fuzzer for NullGLCanvas for use on OSS-Fuzz.

Bug: 827225
Change-Id: Icb30c0c234326340213af0cc402a4124dd0336b3
Reviewed-on: https://skia-review.googlesource.com/117150
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>

fuzz/oss_fuzz/FuzzNullGLCanvas.cpp

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2018 Google, LLC
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "../Fuzz.h"
+
+void fuzz_NullGLCanvas(Fuzz* f);
+
+extern "C" {
+
+    // Set default LSAN options.
+    const char *__lsan_default_options() {
+        // Don't print the list of LSAN suppressions on every execution.
+        return "print_suppressions=0";
+    }
+
+    int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
+        auto fuzz = Fuzz(SkData::MakeWithoutCopy(data, size));
+        fuzz_NullGLCanvas(&fuzz);
+        return 0;
+    }
+}  // extern "C"