Fixed more fuzzer issues

src/core/SkImageInfo.cpp

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkImageInfo.h"
 #include "SkFlattenableBuffers.h"
 
+static bool alpha_type_is_valid(SkAlphaType alphaType) {
+    return (alphaType >= 0) && (alphaType <= kLastEnum_SkAlphaType);
+}
+
+static bool color_type_is_valid(SkColorType colorType) {
+    return (colorType >= 0) && (colorType <= kLastEnum_SkColorType);
+}
+
 void SkImageInfo::unflatten(SkFlattenableReadBuffer& buffer) {
     fWidth = buffer.read32();
     fHeight = buffer.read32();
 
     uint32_t packed = buffer.read32();
     SkASSERT(0 == (packed >> 16));
     fAlphaType = (SkAlphaType)((packed >> 8) & 0xFF);
     fColorType = (SkColorType)((packed >> 0) & 0xFF);
+    buffer.validate(alpha_type_is_valid(fAlphaType) &&
+                    color_type_is_valid(fColorType));
 }
 
 void SkImageInfo::flatten(SkFlattenableWriteBuffer& buffer) const {
     buffer.write32(fWidth);
     buffer.write32(fHeight);
 
     SkASSERT(0 == (fAlphaType & ~0xFF));
     SkASSERT(0 == (fColorType & ~0xFF));
     uint32_t packed = (fAlphaType << 8) | fColorType;
     buffer.write32(packed);
 }