Do not zero-initialize RawPtr.

Source/core/css/CSSCalculationValueTest.cpp

 /*
  * Copyright (c) 2013, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 36 matching lines @@
     EXPECT_TRUE(
         expression->equals(
             *CSSCalcValue::createExpressionNode(
                 expression->toCalcValue(CSSToLengthConversionData(style, style, 0)).get(),
                 style->effectiveZoom()).get()));
 }
 
 TEST(CSSCalculationValue, CreateExpressionNodeFromLength)
 {
     RefPtr<RenderStyle> style = RenderStyle::create();
-    RefPtrWillBeRawPtr<CSSCalcExpressionNode> expected;
-    RefPtrWillBeRawPtr<CSSCalcExpressionNode> actual;
+    RefPtrWillBeRawPtr<CSSCalcExpressionNode> expected = nullptr;
+    RefPtrWillBeRawPtr<CSSCalcExpressionNode> actual = nullptr;
 
     expected = CSSCalcValue::createExpressionNode(CSSPrimitiveValue::create(10, CSSPrimitiveValue::CSS_PX), true);
     actual = CSSCalcValue::createExpressionNode(Length(10, WebCore::Fixed), style->effectiveZoom());
     EXPECT_TRUE(actual->equals(*expected.get()));
 
     expected = CSSCalcValue::createExpressionNode(
         CSSCalcValue::createExpressionNode(CSSPrimitiveValue::create(10, CSSPrimitiveValue::CSS_PX), true),
         CSSCalcValue::createExpressionNode(CSSPrimitiveValue::create(20, CSSPrimitiveValue::CSS_PX), true),
         CalcAdd);
     actual = CSSCalcValue::createExpressionNode(
@@ skipping 33 matching lines @@
     actual = CSSCalcValue::createExpressionNode(
         Length(CalculationValue::create(
             adoptPtr(new CalcExpressionBlendLength(Length(50, WebCore::Fixed), Length(60, WebCore::Fixed), 0.75)),
             ValueRangeAll)),
         style->effectiveZoom());
     EXPECT_TRUE(actual->equals(*expected.get()));
 }
 
 TEST(CSSCalculationValue, CreateExpressionNodeFromLengthFromExpressionNode)
 {
-    RefPtrWillBeRawPtr<CSSCalcExpressionNode> expression;
     RefPtr<RenderStyle> style = RenderStyle::createDefaultStyle();
     style->setEffectiveZoom(5);
 
     testExpression(
         CSSCalcValue::createExpressionNode(CSSPrimitiveValue::create(10, CSSPrimitiveValue::CSS_PX), true),
         style.get());
 
     testExpression(
         CSSCalcValue::createExpressionNode(
             CSSCalcValue::createExpressionNode(CSSPrimitiveValue::create(10, CSSPrimitiveValue::CSS_PX), true),
@@ skipping 16 matching lines @@
                 CalcMultiply),
             CSSCalcValue::createExpressionNode(
                 CSSCalcValue::createExpressionNode(CSSPrimitiveValue::create(60, CSSPrimitiveValue::CSS_PX), true),
                 CSSCalcValue::createExpressionNode(CSSPrimitiveValue::create(0.75, CSSPrimitiveValue::CSS_NUMBER), false),
                 CalcMultiply),
             CalcAdd),
         style.get());
 }
 
 }