Relax the assert in SkReadBuffer::setPictureVersion().

include/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 28 matching lines @@
     SkReadBuffer();
     SkReadBuffer(const void* data, size_t size);
     SkReadBuffer(SkStream* stream);
     virtual ~SkReadBuffer();
 
     /** Return the version of the serialized picture this buffer holds, or 0 if unset. */
     int pictureVersion() const { return fPictureVersion; }
 
     /** This may be called at most once; most clients of SkReadBuffer should not mess with it. */
     void setPictureVersion(int version) {
-        SkASSERT(0 == fPictureVersion);
+        SkASSERT(0 == fPictureVersion || version == fPictureVersion);
         fPictureVersion = version;
     }
 
     enum Flags {
         kCrossProcess_Flag  = 1 << 0,
         kScalarIsFloat_Flag = 1 << 1,
         kPtrIs64Bit_Flag    = 1 << 2,
         kValidation_Flag    = 1 << 3,
     };
 
@@ skipping 148 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