Revert of Make SkPicture/SkImageGenerator default to SkCodec

tools/LazyDecodeBitmap.cpp

+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "LazyDecodeBitmap.h"
+
+#include "SkData.h"
+#include "SkDiscardableMemoryPool.h"
+#include "SkImageGeneratorPriv.h"
+#include "SkForceLinking.h"
+
+#include "SkCommandLineFlags.h"
+
+__SK_FORCE_IMAGE_DECODER_LINKING;
+
+DEFINE_bool(useVolatileCache, false, "Use a volatile cache for deferred image decoding pixels. "
+            "Only meaningful if --deferImageDecoding is set to true and the platform has an "
+            "implementation.");
+
+//  Fits SkPicture::InstallPixelRefProc call signature.
+//  Used in SkPictureData::CreateFromStream
+bool sk_tools::LazyDecodeBitmap(const void* src, size_t length, SkBitmap* dst) {
+    SkAutoDataUnref data(SkData::NewWithCopy(src, length));
+    if (nullptr == data.get()) {
+        return false;
+    }
+
+    SkAutoTDelete<SkImageGenerator> gen(SkImageGenerator::NewFromEncoded(data));
+    if (nullptr == gen.get()) {
+        return false;
+    }
+    const SkImageInfo info = gen->getInfo();
+    SkDiscardableMemory::Factory* pool = nullptr;
+    if ((!FLAGS_useVolatileCache) || (info.width() * info.height() < 32 * 1024)) {
+        // how to do switching with SkDiscardableMemory.
+        pool = SkGetGlobalDiscardableMemoryPool();
+        // Only meaningful if platform has a default discardable
+        // memory implementation that differs from the global DM pool.
+    }
+    return SkDEPRECATED_InstallDiscardablePixelRef(gen.detach(), nullptr, dst, pool);
+}