Fix FontCacheKey-keyed HashMap usage in core/css

third_party/WebKit/Source/core/css/CSSFontFaceSourceTest.cpp

+// Copyright 2016 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 "core/css/CSSFontFaceSource.h"
+
+#include "platform/fonts/FontCacheKey.h"
+#include "platform/fonts/FontDescription.h"
+#include "platform/fonts/FontPlatformData.h"
+#include "platform/fonts/SimpleFontData.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace blink {
+
+class DummyFontFaceSource : public CSSFontFaceSource {
+public:
+    PassRefPtr<SimpleFontData> createFontData(const FontDescription&) override
+    {
+        return SimpleFontData::create(FontPlatformData(adoptRef(SkTypeface::RefDefault()), "", 0, false, false));
+    }
+
+    DummyFontFaceSource() { }
+
+    PassRefPtr<SimpleFontData> getFontDataForSize(float size)
+    {
+        FontDescription fontDescription;
+        fontDescription.setSizeAdjust(size);
+        fontDescription.setAdjustedSize(size);
+        return getFontData(fontDescription);
+    }
+};
+
+namespace {
+
+unsigned simulateHashCalculation(float size)
+{
+    FontDescription fontDescription;
+    fontDescription.setSizeAdjust(size);
+    fontDescription.setAdjustedSize(size);
+    return fontDescription.cacheKey(FontFaceCreationParams()).hash();
+}
+
+}
+
+TEST(CSSFontFaceSourceTest, HashCollision)
+{
+    DummyFontFaceSource fontFaceSource;
+    // Even if the hash value collide, fontface cache should return different value for different fonts.
+    EXPECT_EQ(simulateHashCalculation(2821), simulateHashCalculation(3346));
+    EXPECT_NE(fontFaceSource.getFontDataForSize(2821), fontFaceSource.getFontDataForSize(3346));
+}
+
+} // namespace blink