Improve RAII of StyleResolverState.

Source/core/css/resolver/StyleResolverState.cpp

Index: Source/core/css/resolver/StyleResolverState.cpp
diff --git a/Source/core/css/resolver/StyleResolverState.cpp b/Source/core/css/resolver/StyleResolverState.cpp
index b71a93d26e0c468e25faaac22a6ba6c964247016..bdad2520f3986bba3977eb318da9d752405b70b2 100644
--- a/Source/core/css/resolver/StyleResolverState.cpp
+++ b/Source/core/css/resolver/StyleResolverState.cpp
@@ -29,20 +29,36 @@
 
 namespace blink {
 
-StyleResolverState::StyleResolverState(Document& document, Element* element, RenderStyle* parentStyle)
-    : m_elementContext(element ? ElementResolveContext(*element) : ElementResolveContext(document))
+StyleResolverState::StyleResolverState(Document& document, const ElementResolveContext& elementContext, PassRefPtr<RenderStyle> style, PassRefPtr<RenderStyle> parentStyle)
+    : m_elementContext(elementContext)
     , m_document(document)
-    , m_style(nullptr)
-    , m_cssToLengthConversionData(0, rootElementStyle(), document.renderView())
-    , m_parentStyle(parentStyle)
+    , m_style(style)
+    , m_cssToLengthConversionData(m_style.get(), rootElementStyle(), document.renderView())
+    , m_parentStyle(parentStyle ? parentStyle : RenderStyle::clone(m_style.get()))
     , m_applyPropertyToRegularStyle(true)
     , m_applyPropertyToVisitedLinkStyle(false)
-    , m_fontBuilder(document)
+    , m_fontBuilder(document, m_style.get())
     , m_styleMap(*this, m_elementStyleResources)
 {
-    if (!parentStyle && m_elementContext.parentNode())
-        m_parentStyle = m_elementContext.parentNode()->renderStyle();
+    ASSERT(this->style());
+    ASSERT(this->parentStyle());
+    ASSERT(document.isActive());
+    m_elementStyleResources.setDeviceScaleFactor(document.frameHost()->deviceScaleFactor());
+}
 
+StyleResolverState::StyleResolverState(Document& document, Element* element, PassRefPtr<RenderStyle> style, RenderStyle* parentStyle)
+    : m_elementContext(element ? ElementResolveContext(*element, parentStyle) : ElementResolveContext(document))
+    , m_document(document)
+    , m_style(style)
+    , m_cssToLengthConversionData(m_style.get(), rootElementStyle(), document.renderView())
+    , m_parentStyle(m_elementContext.parentStyle() ? m_elementContext.parentStyle() : RenderStyle::clone(m_style.get()))
+    , m_applyPropertyToRegularStyle(true)
+    , m_applyPropertyToVisitedLinkStyle(false)
+    , m_fontBuilder(document, m_style.get())
+    , m_styleMap(*this, m_elementStyleResources)
+{
+    ASSERT(this->style());
+    ASSERT(this->parentStyle());
     ASSERT(document.isActive());
     m_elementStyleResources.setDeviceScaleFactor(document.frameHost()->deviceScaleFactor());
 }