Propagate validation errors

src/core/SkPictureData.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 SkPictureData_DEFINED
 #define SkPictureData_DEFINED
 
@@ skipping 99 matching lines @@
     }
 
     SkDrawable* getDrawable(SkReadBuffer* reader) const {
         int index = reader->readInt();
         SkASSERT(index > 0 && index <= fDrawableCount);
         return fDrawableRefs[index - 1];
     }
 
     const SkPaint* getPaint(SkReadBuffer* reader) const {
         const int index = reader->readInt() - 1;
+        if (index == -1) {  // recorder wrote a zero for no paint (likely drawimage)
+            return nullptr;
+        }
         return reader->validateIndex(index, fPaints.count()) ? &fPaints[index] : nullptr;
     }
 
     const SkTextBlob* getTextBlob(SkReadBuffer* reader) const {
         const int index = reader->readInt() - 1;
         return reader->validateIndex(index, fTextBlobCount) ? fTextBlobRefs[index] : nullptr;
     }
 
 #if SK_SUPPORT_GPU
     /**
@@ skipping 49 matching lines @@
 
     const SkPictInfo fInfo;
 
     static void WriteFactories(SkWStream* stream, const SkFactorySet& rec);
     static void WriteTypefaces(SkWStream* stream, const SkRefCntSet& rec);
 
     void initForPlayback() const;
 };
 
 #endif