More regular Platform implementations in unit tests (reland.)

third_party/WebKit/Source/platform/fonts/FontCacheTest.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "platform/fonts/FontCache.h"
 
 #include "platform/fonts/FontDescription.h"
 #include "platform/fonts/SimpleFontData.h"
+#include "platform/testing/TestingPlatformSupport.h"
 #include "public/platform/Platform.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace blink {
 
-class EmptyPlatform : public Platform {
+class EmptyPlatform : public TestingPlatformSupport {
 public:
     EmptyPlatform() {}
     ~EmptyPlatform() override {}
-    void cryptographicallyRandomValues(unsigned char* buffer, size_t length) override
-    {
-        RELEASE_ASSERT_NOT_REACHED();
-    }
 };
 
 TEST(FontCache, getLastResortFallbackFont)
 {
     FontCache* fontCache = FontCache::fontCache();
     ASSERT_TRUE(fontCache);
 
-    Platform* oldPlatform = Platform::current();
-    OwnPtr<EmptyPlatform> platform = adoptPtr(new EmptyPlatform);
-    Platform::initialize(platform.get());
+    EmptyPlatform platform;
 
     FontDescription fontDescription;
     fontDescription.setGenericFamily(FontDescription::StandardFamily);
     RefPtr<SimpleFontData> fontData = fontCache->getLastResortFallbackFont(fontDescription, Retain);
     EXPECT_TRUE(fontData);
 
     fontDescription.setGenericFamily(FontDescription::SansSerifFamily);
     fontData = fontCache->getLastResortFallbackFont(fontDescription, Retain);
     EXPECT_TRUE(fontData);
-
-    Platform::initialize(oldPlatform);
 }
 
 } // namespace blink