Fixed issues found by fuzzer

include/effects/SkLightingImageFilter.h

 /*
  * Copyright 2012 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkLightingImageFilter_DEFINED
 #define SkLightingImageFilter_DEFINED
 
 #include "SkImageFilter.h"
 #include "SkColor.h"
 
 class SK_API SkPoint3 {
 public:
     SkPoint3() {}
     SkPoint3(SkScalar x, SkScalar y, SkScalar z)
       : fX(x), fY(y), fZ(z) {}
     SkScalar dot(const SkPoint3& other) const {
         return SkScalarMul(fX, other.fX)
              + SkScalarMul(fY, other.fY)
              + SkScalarMul(fZ, other.fZ);
     }
     SkScalar maxComponent() const {
         return fX > fY ? (fX > fZ ? fX : fZ) : (fY > fZ ? fY : fZ);
     }
     void normalize() {
-        SkScalar scale = SkScalarInvert(SkScalarSqrt(dot(*this)));
+        // Small epsilon is added to prevent division by 0.
+        SkScalar scale = SkScalarInvert(SkScalarSqrt(dot(*this)) + SK_ScalarNearlyZero);
         fX = SkScalarMul(fX, scale);
         fY = SkScalarMul(fY, scale);
         fZ = SkScalarMul(fZ, scale);
     }
     SkPoint3 operator*(SkScalar scalar) const {
         return SkPoint3(SkScalarMul(fX, scalar),
                         SkScalarMul(fY, scalar),
                         SkScalarMul(fZ, scalar));
     }
     SkPoint3 operator-(const SkPoint3& other) const {
@@ skipping 43 matching lines @@
     const SkLight* light() const { return fLight; }
     SkScalar surfaceScale() const { return fSurfaceScale; }
 
 private:
     typedef SkImageFilter INHERITED;
     SkLight* fLight;
     SkScalar fSurfaceScale;
 };
 
 #endif