Improve ColorStopOptimizer safety

src/effects/gradients/SkGradientShader.cpp

 /*
  * Copyright 2006 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.
  */
 
 #include "Sk4fLinearGradient.h"
 #include "SkGradientShaderPriv.h"
 #include "SkLinearGradient.h"
@@ skipping 827 matching lines @@
 
     bool flipGradient = startRadius > endRadius;
 
     SkGradientShaderBase::Descriptor desc;
 
     if (!flipGradient) {
         desc_init(&desc, opt.fColors, opt.fPos, opt.fCount, mode, flags, localMatrix);
         return sk_make_sp<SkTwoPointConicalGradient>(start, startRadius, end, endRadius,
                                                      flipGradient, desc);
     } else {
-        SkAutoSTArray<8, SkColor> colorsNew(colorCount);
-        SkAutoSTArray<8, SkScalar> posNew(colorCount);
-        for (int i = 0; i < colorCount; ++i) {
-            colorsNew[i] = opt.fColors[colorCount - i - 1];
+        SkAutoSTArray<8, SkColor> colorsNew(opt.fCount);
+        SkAutoSTArray<8, SkScalar> posNew(opt.fCount);
+        for (int i = 0; i < opt.fCount; ++i) {
+            colorsNew[i] = opt.fColors[opt.fCount - i - 1];
         }
 
         if (pos) {
-            for (int i = 0; i < colorCount; ++i) {
-                posNew[i] = 1 - opt.fPos[colorCount - i - 1];
+            for (int i = 0; i < opt.fCount; ++i) {
+                posNew[i] = 1 - opt.fPos[opt.fCount - i - 1];
             }
-            desc_init(&desc, colorsNew.get(), posNew.get(), colorCount, mode, flags, localMatrix);
+            desc_init(&desc, colorsNew.get(), posNew.get(), opt.fCount, mode, flags, localMatrix);
         } else {
-            desc_init(&desc, colorsNew.get(), nullptr, colorCount, mode, flags, localMatrix);
+            desc_init(&desc, colorsNew.get(), nullptr, opt.fCount, mode, flags, localMatrix);
         }
 
         return sk_make_sp<SkTwoPointConicalGradient>(end, endRadius, start, startRadius,
                                                      flipGradient, desc);
     }
 }
 
 sk_sp<SkShader> SkGradientShader::MakeSweep(SkScalar cx, SkScalar cy,
                                         const SkColor colors[],
                                         const SkScalar pos[],
@@ skipping 637 matching lines @@
             (*stops)[i] = stop;
             stop = i < outColors - 1 ? stop + random->nextUScalar1() * (1.f - stop) : 1.f;
         }
     }
     *tm = static_cast<SkShader::TileMode>(random->nextULessThan(SkShader::kTileModeCount));
 
     return outColors;
 }
 
 #endif