Fixing clusterfuzz issue

src/opts/SkXfermode_opts_SSE2.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorPriv.h"
 #include "SkColor_opts_SSE2.h"
 #include "SkMathPriv.h"
@@ skipping 626 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 
 typedef __m128i (*SkXfermodeProcSIMD)(const __m128i& src, const __m128i& dst);
 
 extern SkXfermodeProcSIMD gSSE2XfermodeProcs[];
 
 SkSSE2ProcCoeffXfermode::SkSSE2ProcCoeffXfermode(SkReadBuffer& buffer)
     : INHERITED(buffer) {
     fProcSIMD = reinterpret_cast<void*>(gSSE2XfermodeProcs[this->getMode()]);
+    buffer.validate(fProcSIMD != NULL);

[Stephen White, 2014/06/02 13:13:35]

Not new to this patch, but I wonder why we have such processor-specific
subclasses at all. Shouldn't the SKP format be processor-indepdendent? I.e.,
shouldn't we serialize generic implementations, and have the processing code
initialize callbacks for the platform it's running on?

 }
 
 void SkSSE2ProcCoeffXfermode::xfer32(SkPMColor dst[], const SkPMColor src[],
                                      int count, const SkAlpha aa[]) const {
     SkASSERT(dst && src && count >= 0);
 
     SkXfermodeProc proc = this->getProc();
     SkXfermodeProcSIMD procSIMD = reinterpret_cast<SkXfermodeProcSIMD>(fProcSIMD);
     SkASSERT(procSIMD != NULL);
 
@@ skipping 152 matching lines @@
 
 SkProcCoeffXfermode* SkPlatformXfermodeFactory_impl_SSE2(const ProcCoeff& rec,
                                                          SkXfermode::Mode mode) {
     void* procSIMD = reinterpret_cast<void*>(gSSE2XfermodeProcs[mode]);
 
     if (procSIMD != NULL) {
         return SkNEW_ARGS(SkSSE2ProcCoeffXfermode, (rec, mode, procSIMD));
     }
     return NULL;
 }