Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/core/animation/LengthPairStyleInterpolation.h

 // Copyright 2014 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.
 
 #ifndef LengthPairStyleInterpolation_h
 #define LengthPairStyleInterpolation_h
 
 #include "core/CoreExport.h"
 #include "core/animation/StyleInterpolation.h"
 #include "platform/Length.h"
@@ skipping 11 matching lines @@
 
     void apply(StyleResolverState&) const override;
 
 private:
     LengthPairStyleInterpolation(PassOwnPtr<InterpolableValue> start, PassOwnPtr<InterpolableValue> end, CSSPropertyID id, InterpolationRange range)
         : StyleInterpolation(std::move(start), std::move(end), id), m_range(range)
     {
     }
 
     static PassOwnPtr<InterpolableValue> lengthPairToInterpolableValue(const CSSValue&);
-    static PassRefPtrWillBeRawPtr<CSSValue> interpolableValueToLengthPair(InterpolableValue*, InterpolationRange);
+    static RawPtr<CSSValue> interpolableValueToLengthPair(InterpolableValue*, InterpolationRange);
 
     InterpolationRange m_range;
 
     friend class LengthPairStyleInterpolationTest;
 };
 
 } // namespace blink
 
 #endif // LengthPairStyleInterpolation_h