Harden degenerate gradient context handling

src/effects/gradients/SkRadialGradient.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkRadialGradient.h"
 #include "SkNx.h"
 
@@ skipping 26 matching lines @@
     : SkGradientShaderBase(desc, rad_to_unit_matrix(center, radius))
     , fCenter(center)
     , fRadius(radius) {
 }
 
 size_t SkRadialGradient::onContextSize(const ContextRec&) const {
     return sizeof(RadialGradientContext);
 }
 
 SkShader::Context* SkRadialGradient::onCreateContext(const ContextRec& rec, void* storage) const {
-    return new (storage) RadialGradientContext(*this, rec);
+    return CheckedCreateContext<RadialGradientContext>(storage, *this, rec);
 }
 
 SkRadialGradient::RadialGradientContext::RadialGradientContext(
         const SkRadialGradient& shader, const ContextRec& rec)
     : INHERITED(shader, rec) {}
 
 SkShader::GradientType SkRadialGradient::asAGradient(GradientInfo* info) const {
     if (info) {
         commonAsAGradient(info);
         info->fPoint[0] = fCenter;
@@ skipping 319 matching lines @@
     str->appendScalar(fCenter.fY);
     str->append(") radius: ");
     str->appendScalar(fRadius);
     str->append(" ");
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif