Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/core/css/cssom/NumberValue.h

Index: third_party/WebKit/Source/core/css/cssom/NumberValue.h
diff --git a/third_party/WebKit/Source/core/css/cssom/NumberValue.h b/third_party/WebKit/Source/core/css/cssom/NumberValue.h
index 142affb7fa963222ba09cddb65484efcb1fe8bd6..33d60652c988fcb209337c8222a7fe0e907afbd5 100644
--- a/third_party/WebKit/Source/core/css/cssom/NumberValue.h
+++ b/third_party/WebKit/Source/core/css/cssom/NumberValue.h
@@ -28,7 +28,7 @@ public:
         m_value = value;
     }
 
-    PassRefPtrWillBeRawPtr<CSSValue> toCSSValue() const override
+    RawPtr<CSSValue> toCSSValue() const override
     {
         return cssValuePool().createValue(m_value, CSSPrimitiveValue::UnitType::
 Number);