Optionally enable SkValidatingReadBuffer in SkPictureImageFilter

src/core/SkReadBuffer.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkReadBuffer_DEFINED
 #define SkReadBuffer_DEFINED
 
@@ skipping 21 matching lines @@
     #define DEBUG_NON_DETERMINISTIC_ASSERT
 #endif
 
 class SkReadBuffer {
 public:
     SkReadBuffer();
     SkReadBuffer(const void* data, size_t size);
     SkReadBuffer(SkStream* stream);
     virtual ~SkReadBuffer();
 
+    virtual SkReadBuffer* clone(const void* data, size_t size) const {
+        return new SkReadBuffer(data, size);
+    }
+
     enum Version {
         /*
         kFilterLevelIsEnum_Version         = 23,
         kGradientFlippedFlag_Version       = 24,
         kDashWritesPhaseIntervals_Version  = 25,
         kColorShaderNoBool_Version         = 26,
         kNoUnitMappers_Version             = 27,
         kNoMoreBitmapFlatten_Version       = 28,
         kSimplifyLocalMatrix_Version       = 30,
         kImageFilterUniqueID_Version       = 31,
@@ skipping 181 matching lines @@
     SkPicture::InstallPixelRefProc fBitmapDecoder;
 
 #ifdef DEBUG_NON_DETERMINISTIC_ASSERT
     // Debugging counter to keep track of how many bitmaps we
     // have decoded.
     int fDecodedBitmapIndex;
 #endif // DEBUG_NON_DETERMINISTIC_ASSERT
 };
 
 #endif // SkReadBuffer_DEFINED