Revert of Port uses of SkLazyPtr to SkOncePtr.

tests/LazyPtrTest.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 "Test.h"
+#include "SkLazyPtr.h"
+#include "SkRunnable.h"
+#include "SkTaskGroup.h"
+
+namespace {
+
+struct CreateIntFromFloat {
+    CreateIntFromFloat(float val) : fVal(val) {}
+    int* operator()() const { return new int((int)fVal); }
+    float fVal;
+};
+
+// As a template argument this must have external linkage.
+void custom_destroy(int* ptr) { *ptr = 99; }
+
+} // namespace
+
+DEF_TEST(LazyPtr, r) {
+    // Basic usage: calls new int.
+    SkLazyPtr<int> lazy;
+    int* ptr = lazy.get();
+    REPORTER_ASSERT(r, ptr);
+    REPORTER_ASSERT(r, lazy.get() == ptr);
+
+    // Advanced usage: calls a functor.
+    SkLazyPtr<int> lazyFunctor;
+    int* six = lazyFunctor.get(CreateIntFromFloat(6.4f));
+    REPORTER_ASSERT(r, six);
+    REPORTER_ASSERT(r, 6 == *six);
+
+    // Just makes sure this is safe.
+    SkLazyPtr<double> neverRead;
+
+    // SkLazyPtr supports custom destroy methods.
+    {
+        SkLazyPtr<int, custom_destroy> customDestroy;
+        ptr = customDestroy.get();
+        // custom_destroy called here.
+    }
+    REPORTER_ASSERT(r, ptr);
+    REPORTER_ASSERT(r, 99 == *ptr);
+    // Since custom_destroy didn't actually delete ptr, we do now.
+    delete ptr;
+}
+
+DEF_TEST(LazyPtr_Threaded, r) {
+    static const int kRacers = 321;
+
+    // Race to intialize the pointer by calling .get().
+    SkLazyPtr<int> lazy;
+    int* seen[kRacers];
+
+    sk_parallel_for(kRacers, [&](int i) {
+        seen[i] = lazy.get();
+    });
+
+    // lazy.get() should return the same pointer to all threads.
+    for (int i = 1; i < kRacers; i++) {
+        REPORTER_ASSERT(r, seen[i] != nullptr);
+        REPORTER_ASSERT(r, seen[i] == seen[0]);
+    }
+}