If we pass no bytes, use the fuzz binary itself.

fuzz/fuzz.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Fuzz.h"
 #include "SkCommandLineFlags.h"
 #include <signal.h>
 #include <stdlib.h>
 
 DEFINE_string2(bytes, b, "", "A path to a file containing fuzzed bytes.");
 DEFINE_string2(match, m, "", "The usual --match, applied to DEF_FUZZ names.");
 
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
 
-    if (FLAGS_bytes.isEmpty()) {
-        SkDebugf("Usage: %s -b <path/to/fuzzed.data> [-m pattern]\n", argv[0]);
-        return 1;
-    }
-    SkAutoTUnref<SkData> bytes(SkData::NewFromFileName(FLAGS_bytes[0]));
+    const char* path = FLAGS_bytes.isEmpty() ? argv[0] : FLAGS_bytes[0];
+    SkAutoTUnref<SkData> bytes(SkData::NewFromFileName(path));
 
     for (auto r = SkTRegistry<Fuzzable>::Head(); r; r = r->next()) {
         auto fuzzable = r->factory();
         if (!SkCommandLineFlags::ShouldSkip(FLAGS_match, fuzzable.name)) {
             SkDebugf("Fuzzing %s...\n", fuzzable.name);
             Fuzz fuzz(bytes);
             fuzzable.fn(&fuzz);
         }
     }
     return 0;
@@ skipping 14 matching lines @@
     T val;
     memcpy(&val, fBytes->bytes() + fNextByte, sizeof(T));
     fNextByte += sizeof(T);
     return val;
 }
 
 uint8_t  Fuzz::nextB() { return this->nextT<uint8_t >(); }
 uint32_t Fuzz::nextU() { return this->nextT<uint32_t>(); }
 float    Fuzz::nextF() { return this->nextT<float   >(); }