Revert of Reopened: Caching the result of readPixelsSupported

src/core/SkTHashCache.h

-/*
- * Copyright 2014 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SkTHASHCACHE_DEFINED
-#define SkTHASHCACHE_DEFINED
-
-#include "SkTypes.h"
-#include "SkTDynamicHash.h"
-
-template <typename T,
-typename Key,
-typename Traits = T,
-int kGrowPercent = 75 >
-class SkTHashCache : public SkNoncopyable {
-public:
-
-    SkTHashCache() {
-        this->reset();
-    }
-
-    ~SkTHashCache() {
-        this->clear();
-    }
-
-    T* find(const Key& key) const {
-        return fDict->find(key);
-    }
-
-    /**
-     *  If element already in cache, return immediately the cached value
-     */
-    T& add(const T& add) {
-        Key key = Traits::GetKey(add);
-        if (T* val = this->find(key)) {
-            return *val;
-        }
-
-        T* element = SkNEW_ARGS(T, (add));
-
-        fDict->add(element);
-
-        return *element;
-    }
-
-    int size() const {
-        return fDict->count();
-    }
-
-    void reset() {
-        this->clear();
-
-        fDict.reset(SkNEW(DictType));
-    }
-
-private:
-    typedef SkTDynamicHash<T, Key, Traits, kGrowPercent> DictType;
-
-    void clear() {
-        if (fDict.get()) {
-            typename DictType::Iter it(fDict.get());
-
-            while (!it.done()) {
-                SkDELETE(&(*it));
-                ++it;
-            }
-        }
-    }
-
-    SkAutoTDelete<DictType> fDict;
-};
-
-#endif  /* SkHASHCACHE_DEFINED */
-