Cleanup SkPicture* classes a bit

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 "SkPictureData.h"
 #include "SkPicturePlayback.h"
@@ skipping 48 matching lines @@
     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;
 }
 
 const SkPicture::OperationList* SkPicturePlayback::getActiveOps(const SkCanvas* canvas) {
 
-    if (fUseBBH && NULL != fPictureData->fStateTree && NULL != fPictureData->fBoundingHierarchy) {
+    if (fUseBBH) {
         SkRect clipBounds;
         if (canvas->getClipBounds(&clipBounds)) {
             SkIRect query;
             clipBounds.roundOut(&query);
 
             return fPictureData->getActiveOps(query);
         }
     } 
 
     return NULL;
 }
 
 // Initialize the state tree iterator. Return false if there is nothing left to draw.
 bool SkPicturePlayback::initIterator(SkPictureStateTree::Iterator* iter, 
                                      SkCanvas* canvas,
                                      const SkPicture::OperationList *activeOpsList) {
 
     if (NULL != activeOpsList) {
         if (0 == activeOpsList->numOps()) {
             return false;  // nothing to draw
         }
 
-        fPictureData->fStateTree->initIterator(iter, activeOpsList->fOps, canvas);
+        fPictureData->initIterator(iter, activeOpsList->fOps, canvas);
     }
 
     return true;
 }
 
 // If 'iter' is valid use it to skip forward through the picture.
 void SkPicturePlayback::StepIterator(SkPictureStateTree::Iterator* iter, SkReader32* reader) {
     if (iter->isValid()) {
         uint32_t skipTo = iter->nextDraw();
         if (SkPictureStateTree::Iterator::kDrawComplete == skipTo) {
@@ skipping 374 matching lines @@
         case TRANSLATE: {
             SkScalar dx = reader->readScalar();
             SkScalar dy = reader->readScalar();
             canvas->translate(dx, dy);
         } break;
         default:
             SkASSERT(0);
     }
 }