Switch to a more complete method of filtering hoisted layers

src/gpu/GrRecordReplaceDraw.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 "GrContext.h"
 #include "GrLayerCache.h"
 #include "GrRecordReplaceDraw.h"
 #include "SkCanvasPriv.h"
 #include "SkGrPixelRef.h"
 #include "SkImage.h"
 #include "SkRecordDraw.h"
 #include "SkRecords.h"
 
 static inline void wrap_texture(GrTexture* texture, int width, int height, SkBitmap* result) {
     SkImageInfo info = SkImageInfo::MakeN32Premul(width, height);
     result->setInfo(info);
     result->setPixelRef(SkNEW_ARGS(SkGrPixelRef, (info, texture)))->unref();
 }
 
 static inline void draw_replacement_bitmap(GrCachedLayer* layer, SkCanvas* canvas) {
 
+    // Some image filter can totally filter away a layer (e.g., SkPictureImageFilter's with
+    // no picture).
+    if (!layer->texture()) {
+        return;
+    }
+
     SkBitmap bm;
     wrap_texture(layer->texture(),
                  !layer->isAtlased() ? layer->rect().width()  : layer->texture()->width(),
                  !layer->isAtlased() ? layer->rect().height() : layer->texture()->height(),
                  &bm);
 
     if (layer->isAtlased()) {
         const SkRect src = SkRect::Make(layer->rect());
         const SkRect dst = SkRect::Make(layer->srcIR());
 
@@ skipping 169 matching lines @@
                         const SkMatrix& initialMatrix,
                         SkPicture::AbortCallback* callback) {
     SkAutoCanvasRestore saveRestore(canvas, true /*save now, restore at exit*/);
 
     // TODO: drawablePicts?
     ReplaceDraw draw(canvas, layerCache, NULL, 0,
                      picture, picture,
                      initialMatrix, callback, NULL, 0);
     return draw.draw();
 }