Make stylesheet owner node a reference instead of pointer.

third_party/WebKit/Source/core/dom/StyleEngineTest.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/dom/StyleEngine.h"
 
 #include "core/css/StyleSheetContents.h"
 #include "core/dom/Document.h"
 #include "core/dom/NodeComputedStyle.h"
 #include "core/frame/FrameView.h"
@@ skipping 59 matching lines @@
 }
 
 TEST_F(StyleEngineTest, TextToSheetCache)
 {
     HTMLStyleElement* element = HTMLStyleElement::create(document(), false);
 
     String sheetText("div {}");
     TextPosition minPos = TextPosition::minimumPosition();
     StyleEngineContext context;
 
-    CSSStyleSheet* sheet1 = styleEngine().createSheet(element, sheetText, minPos, context);
+    CSSStyleSheet* sheet1 = styleEngine().createSheet(*element, sheetText, minPos, context);
 
     // Check that the first sheet is not using a cached StyleSheetContents.
     EXPECT_FALSE(sheet1->contents()->isUsedFromTextCache());
 
-    CSSStyleSheet* sheet2 = styleEngine().createSheet(element, sheetText, minPos, context);
+    CSSStyleSheet* sheet2 = styleEngine().createSheet(*element, sheetText, minPos, context);
 
     // Check that the second sheet uses the cached StyleSheetContents for the first.
     EXPECT_EQ(sheet1->contents(), sheet2->contents());
     EXPECT_TRUE(sheet2->contents()->isUsedFromTextCache());
 
     sheet1 = nullptr;
     sheet2 = nullptr;
     element = nullptr;
 
     // Garbage collection should clear the weak reference in the StyleSheetContents cache.
     ThreadState::current()-> collectAllGarbage();
 
     element = HTMLStyleElement::create(document(), false);
-    sheet1 = styleEngine().createSheet(element, sheetText, minPos, context);
+    sheet1 = styleEngine().createSheet(*element, sheetText, minPos, context);
 
     // Check that we did not use a cached StyleSheetContents after the garbage collection.
     EXPECT_FALSE(sheet1->contents()->isUsedFromTextCache());
 }
 
 } // namespace blink