Don't cache parsed stylesheet if it wasn't added to the memory cache.

third_party/WebKit/Source/core/css/CSSStyleSheetResourceTest.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/fetch/CSSStyleSheetResource.h"
 
 #include "core/css/CSSCrossfadeValue.h"
 #include "core/css/CSSImageValue.h"
 #include "core/css/CSSPrimitiveValue.h"
 #include "core/css/CSSProperty.h"
@@ skipping 116 matching lines @@
 
     Resource* imageResource = ImageResource::create(ResourceRequest(imageURL));
     ASSERT_TRUE(imageResource);
     memoryCache()->add(imageResource);
     ASSERT_TRUE(memoryCache()->contains(imageResource));
 
     CSSStyleSheetResource* cssResource = CSSStyleSheetResource::createForTest(ResourceRequest(cssURL), "utf-8");
     cssResource->responseReceived(ResourceResponse(cssURL, "style/css", 0, nullAtom, String()), nullptr);
     cssResource->finish();
 
-    StyleSheetContents* contents = StyleSheetContents::create(CSSParserContext(HTMLStandardMode, nullptr));
+    CSSParserContext parserContext(HTMLStandardMode, nullptr);
+    StyleSheetContents* contents = StyleSheetContents::create(parserContext);
     CSSStyleSheet* sheet = CSSStyleSheet::create(contents, document());
     EXPECT_TRUE(sheet);
 
     contents->checkLoaded();
     cssResource->saveParsedStyleSheet(contents);
 
     // Verify that the cache will have a mapping for |imageResource| at |url|.
     // The underlying |contents| for the stylesheet resource must have a
     // matching cache status.
-    ASSERT_TRUE(memoryCache()->contains(imageResource));
-    ASSERT_FALSE(memoryCache()->contains(cssResource));
-    ASSERT_FALSE(contents->isInMemoryCache());
+    EXPECT_TRUE(memoryCache()->contains(imageResource));
+    EXPECT_FALSE(memoryCache()->contains(cssResource));
+    EXPECT_FALSE(contents->isInMemoryCache());
+    EXPECT_FALSE(cssResource->restoreParsedStyleSheet(parserContext));
 }
 
 } // namespace
 } // namespace blink