private iterator to visit all resource cache entries

src/core/SkPictureShader.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 "SkPictureShader.h"
 
 #include "SkBitmap.h"
@@ skipping 57 matching lines @@
         , fBitmapBytes(bitmapBytes) {}
 
     BitmapShaderKey        fKey;
     SkAutoTUnref<SkShader> fShader;
     size_t                 fBitmapBytes;
 
     const Key& getKey() const override { return fKey; }
     size_t bytesUsed() const override {
         return sizeof(fKey) + sizeof(SkShader) + fBitmapBytes;
     }
+    const char* getCategory() const override { return "bitmap-shader"; }
+    SkDiscardableMemory* diagnostic_only_getDiscardable() const override { return nullptr; }
 
     static bool Visitor(const SkResourceCache::Rec& baseRec, void* contextShader) {
         const BitmapShaderRec& rec = static_cast<const BitmapShaderRec&>(baseRec);
         SkAutoTUnref<SkShader>* result = reinterpret_cast<SkAutoTUnref<SkShader>*>(contextShader);
 
         result->reset(SkRef(rec.fShader.get()));
 
         SkBitmap tile;
         rec.fShader.get()->asABitmap(&tile, NULL, NULL);
         // FIXME: this doesn't protect the pixels from being discarded as soon as we unlock.
@@ skipping 262 matching lines @@
                                              procDataManager, fp);
 }
 #else
 bool SkPictureShader::asFragmentProcessor(GrContext*, const SkPaint&, const SkMatrix&,
                                           const SkMatrix*, GrColor*, GrProcessorDataManager*,
                                           GrFragmentProcessor**) const {
     SkDEBUGFAIL("Should not call in GPU-less build");
     return false;
 }
 #endif