Don't clear FontFaceCache if no @font-face were removed.

Source/core/dom/TreeScopeStyleSheetCollectionTest.cpp

Index: Source/core/dom/TreeScopeStyleSheetCollectionTest.cpp
diff --git a/Source/core/dom/TreeScopeStyleSheetCollectionTest.cpp b/Source/core/dom/TreeScopeStyleSheetCollectionTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..17a37319fd295bd828d8f7084835e061a5ab4226
--- /dev/null
+++ b/Source/core/dom/TreeScopeStyleSheetCollectionTest.cpp
@@ -0,0 +1,152 @@
+// Copyright 2015 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 "core/dom/TreeScopeStyleSheetCollection.h"
+
+#include "core/css/CSSStyleSheet.h"
+#include "core/css/StyleSheetContents.h"
+#include "core/css/parser/CSSParserMode.h"
+#include <gtest/gtest.h>
+
+namespace blink {
+
+class TreeScopeStyleSheetCollectionTest : public testing::Test {
+protected:
+    using SheetVector = WillBeHeapVector<RefPtrWillBeMember<CSSStyleSheet>>;
+    using ContentsVector = WillBeHeapVector<RawPtrWillBeMember<StyleSheetContents>>;
+
+    enum UpdateType {
+        Reconstruct = TreeScopeStyleSheetCollection::Reconstruct,
+        Reset = TreeScopeStyleSheetCollection::Reset,
+        Additive = TreeScopeStyleSheetCollection::Additive
+    };
+
+    static PassRefPtrWillBeRawPtr<CSSStyleSheet> createSheet()
+    {
+        return CSSStyleSheet::create(StyleSheetContents::create(CSSParserContext(HTMLStandardMode, nullptr)));
+    }
+
+    static void compareStyleSheets(const SheetVector& oldStyleSheets, const SheetVector& newStyleSheets, const ContentsVector& expAddedSheets, UpdateType testUpdateType)
+    {
+        ContentsVector addedSheets;
+        UpdateType updateType = static_cast<UpdateType>(TreeScopeStyleSheetCollection::compareStyleSheets(oldStyleSheets, newStyleSheets, addedSheets));
+        EXPECT_EQ(testUpdateType, updateType);
+        EXPECT_EQ(expAddedSheets.size(), addedSheets.size());
+        if (expAddedSheets.size() == addedSheets.size()) {
+            for (unsigned i = 0; i < addedSheets.size(); i++)
+                EXPECT_EQ(expAddedSheets.at(i), addedSheets.at(i));
+        }
+    }
+};
+
+TEST_F(TreeScopeStyleSheetCollectionTest, CompareStyleSheetsAppend)
+{
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet1 = createSheet();
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet2 = createSheet();
+
+    ContentsVector added;
+    SheetVector previous;
+    SheetVector current;
+
+    previous.append(sheet1);
+
+    current.append(sheet1);
+    current.append(sheet2);
+
+    added.append(sheet2->contents());
+
+    compareStyleSheets(previous, current, added, Additive);
+}
+
+TEST_F(TreeScopeStyleSheetCollectionTest, CompareStyleSheetsPrepend)
+{
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet1 = createSheet();
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet2 = createSheet();
+
+    ContentsVector added;
+    SheetVector previous;
+    SheetVector current;
+
+    previous.append(sheet2);
+
+    current.append(sheet1);
+    current.append(sheet2);
+
+    added.append(sheet1->contents());
+
+    compareStyleSheets(previous, current, added, Reconstruct);
+}
+
+TEST_F(TreeScopeStyleSheetCollectionTest, CompareStyleSheetsInsert)
+{
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet1 = createSheet();
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet2 = createSheet();
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet3 = createSheet();
+
+    ContentsVector added;
+    SheetVector previous;
+    SheetVector current;
+
+    previous.append(sheet1);
+    previous.append(sheet3);
+
+    current.append(sheet1);
+    current.append(sheet2);
+    current.append(sheet3);
+
+    added.append(sheet2->contents());
+
+    compareStyleSheets(previous, current, added, Reconstruct);
+}
+
+TEST_F(TreeScopeStyleSheetCollectionTest, CompareStyleSheetsRemove)
+{
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet1 = createSheet();
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet2 = createSheet();
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet3 = createSheet();
+
+    ContentsVector added;
+    SheetVector previous;
+    SheetVector current;
+
+    previous.append(sheet1);
+    previous.append(sheet2);
+    previous.append(sheet3);
+
+    current.append(sheet1);
+    current.append(sheet3);
+
+    added.append(sheet2->contents());
+
+    // This is really the same as Insert. TreeScopeStyleSheetCollection::compareStyleSheets
+    // will assert if you pass an array that is longer as the first parameter.
+    compareStyleSheets(current, previous, added, Reconstruct);
+}
+
+TEST_F(TreeScopeStyleSheetCollectionTest, CompareStyleSheetsInsertRemove)
+{
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet1 = createSheet();
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet2 = createSheet();
+    RefPtrWillBeRawPtr<CSSStyleSheet> sheet3 = createSheet();
+
+    ContentsVector added;
+    SheetVector previous;
+    SheetVector current;
+
+    previous.append(sheet1);
+    previous.append(sheet2);
+
+    current.append(sheet2);
+    current.append(sheet3);
+
+    // TODO(rune@opera.com): This is clearly wrong. We add sheet3 and remove sheet1 and
+    // compareStyleSheets returns sheet2 and sheet3 as added (crbug/475858).
+    added.append(sheet2->contents());
+    added.append(sheet3->contents());
+
+    compareStyleSheets(previous, current, added, Reconstruct);
+}
+
+}