Enable flattening/unflattening with custom unflatten procs

tests/FlattenableCustomFactory.cpp

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkFlattenable.h"
+#include "SkReadBuffer.h"
+#include "SkWriteBuffer.h"
+#include "Test.h"
+
+class IntFlattenable : public SkFlattenable {
+public:
+    IntFlattenable(uint32_t a, uint32_t b, uint32_t c, uint32_t d)
+        : fA(a)
+        , fB(b)
+        , fC(c)
+        , fD(d)
+    {}
+
+    void flatten(SkWriteBuffer& buffer) const override {
+        buffer.writeUInt(fA);
+        buffer.writeUInt(fB);
+        buffer.writeUInt(fC);
+        buffer.writeUInt(fD);
+    }
+
+    Factory getFactory() const override { return nullptr; }
+
+    uint32_t a() const { return fA; }
+    uint32_t b() const { return fB; }
+    uint32_t c() const { return fC; }
+    uint32_t d() const { return fD; }
+
+    const char* getTypeName() const override { return "IntFlattenable"; }
+
+private:
+    uint32_t fA;
+    uint32_t fB;
+    uint32_t fC;
+    uint32_t fD;
+};
+
+static sk_sp<SkFlattenable> custom_create_proc(SkReadBuffer& buffer) {
+    uint32_t a = buffer.readUInt();
+    uint32_t b = buffer.readUInt();
+    uint32_t c = buffer.readUInt();
+    uint32_t d = buffer.readUInt();
+    return sk_sp<SkFlattenable>(new IntFlattenable(a + 1, b + 1, c + 1, d + 1));
+}
+
+DEF_TEST(UnflattenWithCustomFactory, r) {
+    // Create and flatten the test flattenable
+    SkAutoTUnref<SkFlattenable> flattenable(new IntFlattenable(1, 2, 3, 4));
+    SkWriteBuffer writeBuffer;
+    writeBuffer.writeFlattenable(flattenable);
+
+    // Copy the contents of the write buffer into a read buffer
+    sk_sp<SkData> data = SkData::MakeUninitialized(writeBuffer.bytesWritten());
+    writeBuffer.writeToMemory(data->writable_data());
+    SkReadBuffer readBuffer(data->data(), data->size());
+
+    // Register a custom factory with the read buffer
+    readBuffer.setCustomFactory("IntFlattenable", &custom_create_proc);
+
+    // Unflatten and verify the flattenable
+    SkAutoTUnref<IntFlattenable> out((IntFlattenable*) readBuffer.readFlattenable(
+            SkFlattenable::kSkUnused_Type));
+    REPORTER_ASSERT(r, out);
+    REPORTER_ASSERT(r, 2 == out->a());
+    REPORTER_ASSERT(r, 3 == out->b());
+    REPORTER_ASSERT(r, 4 == out->c());
+    REPORTER_ASSERT(r, 5 == out->d());
+}