Optionally enable SkValidatingReadBuffer in SkPictureImageFilter

src/core/SkPicturePlayback.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 "SkCanvas.h"
 #include "SkPatchUtils.h"
 #include "SkPictureData.h"
@@ skipping 67 matching lines @@
 void get_text(SkReadBuffer* reader, TextContainer* text) {
     size_t length = text->fByteLength = reader->readInt();
     text->fText = (const char*)reader->skip(length);
 }
 
 // FIXME: SkBitmaps are stateful, so we need to copy them to play back in multiple threads.
 static SkBitmap shallow_copy(const SkBitmap& bitmap) {
     return bitmap;
 }
 
-void SkPicturePlayback::draw(SkCanvas* canvas, SkPicture::AbortCallback* callback) {
+void SkPicturePlayback::draw(SkCanvas* canvas,
+                             SkPicture::AbortCallback* callback,
+                             const SkReadBuffer* buffer) {
     AutoResetOpID aroi(this);
     SkASSERT(0 == fCurOffset);
 
-    SkReadBuffer reader(fPictureData->opData()->bytes(), fPictureData->opData()->size());
+    SkAutoTDelete<SkReadBuffer> reader;
+    if (buffer) {
+        reader.reset(buffer->clone(fPictureData->opData()->bytes(),
+                                   fPictureData->opData()->size()));
+    } else {
+        reader.reset(new SkReadBuffer(fPictureData->opData()->bytes(),
+                                      fPictureData->opData()->size()));
+    }
 
     // Record this, so we can concat w/ it if we encounter a setMatrix()
     SkMatrix initialMatrix = canvas->getTotalMatrix();
 
     SkAutoCanvasRestore acr(canvas, false);
 
-    while (!reader.eof()) {
+    while (!reader->eof()) {
         if (callback && callback->abort()) {
             return;
         }
 
-        fCurOffset = reader.offset();
+        fCurOffset = reader->offset();
         uint32_t size;
-        DrawType op = ReadOpAndSize(&reader, &size);
+        DrawType op = ReadOpAndSize(reader, &size);
 
-        this->handleOp(&reader, op, size, canvas, initialMatrix);
+        this->handleOp(reader, op, size, canvas, initialMatrix);
     }
 }
 
 void SkPicturePlayback::handleOp(SkReadBuffer* reader,
                                  DrawType op,
                                  uint32_t size,
                                  SkCanvas* canvas,
                                  const SkMatrix& initialMatrix) {
     switch (op) {
         case NOOP: {
@@ skipping 432 matching lines @@
         } break;
         case TRANSLATE: {
             SkScalar dx = reader->readScalar();
             SkScalar dy = reader->readScalar();
             canvas->translate(dx, dy);
         } break;
         default:
             SkASSERTF(false, "Unknown draw type: %d", op);
     }
 }