Do an in-place replacement of SkRandom with Fuzz for FilterFuzz

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 "SkCanvas.h"
 #include "SkCodec.h"
@@ skipping 360 matching lines @@
     }
     SkCanvas canvas(bitmap);
     canvas.drawPicture(pic);
     SkDebugf("[terminated] Success! Decoded and rendered an SkPicture!\n");
     dump_png(bitmap);
     return 0;
 }
 
 Fuzz::Fuzz(SkData* bytes) : fBytes(SkSafeRef(bytes)), fNextByte(0) {}
 
-void Fuzz::signalBug   () { raise(SIGSEGV); }
-void Fuzz::signalBoring() { exit(0); }
+void Fuzz::signalBug   () { SkDebugf("Signal bug\n"); raise(SIGSEGV); }
+void Fuzz::signalBoring() { SkDebugf("Signal boring\n"); exit(0); }
 
 template <typename T>
 T Fuzz::nextT() {
     if (fNextByte + sizeof(T) > fBytes->size()) {
         this->signalBoring();
     }
 
     T val;
     memcpy(&val, fBytes->bytes() + fNextByte, sizeof(T));
     fNextByte += sizeof(T);
     return val;
 }
 
 uint8_t  Fuzz::nextB() { return this->nextT<uint8_t >(); }
 bool  Fuzz::nextBool() { return nextB()&1; }
 uint32_t Fuzz::nextU() { return this->nextT<uint32_t>(); }
 float    Fuzz::nextF() { return this->nextT<float   >(); }
 
+float    Fuzz::nextF1() {
+    // This is the same code as is in SkRandom's nextF()
+    unsigned int floatint = 0x3f800000 | (this->nextU() >> 9);
+    float f = SkBits2Float(floatint) - 1.0f;
+    return f;
+}
 
 uint32_t Fuzz::nextRangeU(uint32_t min, uint32_t max) {
     if (min > max) {
         SkDebugf("Check mins and maxes (%d, %d)\n", min, max);
         this->signalBoring();
     }
     uint32_t range = max - min + 1;
     if (0 == range) {
         return this->nextU();
     } else {
         return min + this->nextU() % range;
     }
 }
 float Fuzz::nextRangeF(float min, float max) {
     if (min > max) {
         SkDebugf("Check mins and maxes (%f, %f)\n", min, max);
         this->signalBoring();
     }
     float f = std::abs(this->nextF());
     if (!std::isnormal(f) && f != 0.0) {
         this->signalBoring();
     }
     return min + fmod(f, (max - min + 1));
 }