[CSS Typed OM] Rearrange StylePropertyMap classes to match the new spec.

third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.cpp

Index: third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.cpp
diff --git a/third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.cpp b/third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.cpp
index a3b94932cb430e8a849801b02a4609064d15cdf1..4dd5635ff4dc7809eda0257b9ed6dfb39536e754 100644
--- a/third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.cpp
+++ b/third_party/WebKit/Source/modules/csspaint/CSSPaintDefinition.cpp
@@ -95,7 +95,7 @@ PassRefPtr<Image> CSSPaintDefinition::paint(
                                           m_hasAlpha ? NonOpaque : Opaque))),
       m_hasAlpha, zoom);
   PaintSize* paintSize = PaintSize::create(specifiedSize);
-  StylePropertyMap* styleMap = FilteredComputedStylePropertyMap::create(
+  StylePropertyMapReadonly* styleMap = FilteredComputedStylePropertyMap::create(
       CSSComputedStyleDeclaration::create(layoutObject.node()),
       m_nativeInvalidationProperties, m_customInvalidationProperties,
       layoutObject.node());