Remove FontDescriptionChangeScope, and let FontBuilder partially apply values.

Source/core/css/resolver/FontBuilder.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 17 matching lines @@
 #include "platform/fonts/FontDescription.h"
 #include "platform/heap/Handle.h"
 #include "wtf/PassRefPtr.h"
 
 namespace blink {
 
 class CSSValue;
 class FontSelector;
 class RenderStyle;
 
-class FontDescriptionChangeScope;
-
 class FontBuilder {
     STACK_ALLOCATED();
     WTF_MAKE_NONCOPYABLE(FontBuilder);
 public:
     FontBuilder(const Document&);
 
-    void setFontDescription(const FontDescription& fd) { m_fontDescription = fd; }
-    const FontDescription& fontDescription() const { return m_fontDescription; }
-
     void setInitial(float effectiveZoom);
 
-    void didChangeFontParameters(bool);
-
-    void inheritFrom(const FontDescription&);
+    void didChangeEffectiveZoom(bool);
+    void didChangeTextOrientation(bool);
+    void didChangeWritingMode(bool);

[rune, 2015/02/03 12:25:40]

I would have removed the bool parameters and checked before calling since
passing false is a no-op.

[andersr, 2015/02/03 15:35:08]

Done.

 
     FontFamily standardFontFamily() const;
     AtomicString standardFontFamilyName() const;
     AtomicString genericFontFamilyName(FontDescription::GenericFamilyType) const;
 
     void setWeight(FontWeight);
     void setSize(const FontDescription::Size&);
     void setStretch(FontStretch);
     void setFamilyDescription(const FontDescription::FamilyDescription&);
     void setFeatureSettings(PassRefPtr<FontFeatureSettings>);
     void setScript(const String& locale);
     void setStyle(FontStyle);
     void setVariant(FontVariant);
     void setVariantLigatures(const FontDescription::VariantLigatures&);
     void setTextRendering(TextRenderingMode);
     void setKerning(FontDescription::Kerning);
     void setFontSmoothing(FontSmoothingMode);
 
     // FIXME: These need to just vend a Font object eventually.
-    void createFont(PassRefPtrWillBeRawPtr<FontSelector>, RenderStyle*, const RenderStyle* parentStyle);
+    void createFont(PassRefPtrWillBeRawPtr<FontSelector>, RenderStyle*);
 
     void createFontForDocument(PassRefPtrWillBeRawPtr<FontSelector>, RenderStyle*);
 
-    // FIXME: These should not be necessary eventually.
-    void setFontDirty(bool fontDirty) { m_fontDirty = fontDirty; }
-    // FIXME: This is only used by an ASSERT in StyleResolver. Remove?
-    bool fontDirty() const { return m_fontDirty; }
+    bool fontDirty() const { return m_flags; }
 
     static FontDescription::FamilyDescription initialFamilyDescription() { return FontDescription::FamilyDescription(initialGenericFamily()); }
     static FontFeatureSettings* initialFeatureSettings() { return nullptr; }
     static FontDescription::GenericFamilyType initialGenericFamily() { return FontDescription::StandardFamily; }
     static FontDescription::Size initialSize() { return FontDescription::Size(FontSize::initialKeywordSize(), 0.0f, false); }
     static TextRenderingMode initialTextRendering() { return AutoTextRendering; }
     static FontVariant initialVariant() { return FontVariantNormal; }
     static FontDescription::VariantLigatures initialVariantLigatures() { return FontDescription::VariantLigatures(); }
     static FontStyle initialStyle() { return FontStyleNormal; }
     static FontDescription::Kerning initialKerning() { return FontDescription::AutoKerning; }
     static FontSmoothingMode initialFontSmoothing() { return AutoSmoothing; }
     static FontStretch initialStretch() { return FontStretchNormal; }
     static FontWeight initialWeight() { return FontWeightNormal; }
 
-    friend class FontDescriptionChangeScope;
-
 private:
 
     void setFamilyDescription(FontDescription&, const FontDescription::FamilyDescription&);
     void setSize(FontDescription&, const FontDescription::Size&);
-    void checkForOrientationChange(RenderStyle*);
+    void updateOrientation(FontDescription&, RenderStyle*);
     // This function fixes up the default font size if it detects that the current generic font family has changed. -dwh
-    void checkForGenericFamilyChange(RenderStyle*, const RenderStyle* parentStyle);
-    void updateComputedSize(RenderStyle*, const RenderStyle* parentStyle);
+    void checkForGenericFamilyChange(const FontDescription&, FontDescription&);
+    void updateSpecifiedSize(FontDescription&, RenderStyle*);
     void updateComputedSize(FontDescription&, RenderStyle*);
 
     float getComputedSizeFromSpecifiedSize(FontDescription&, float effectiveZoom, float specifiedSize);
 
     const Document& m_document;
     FontDescription m_fontDescription;
 
-    // Fontbuilder is responsbile for creating the Font()
-    // object on RenderStyle from various other font-related
-    // properties on RenderStyle. Whenever one of those
-    // is changed, FontBuilder tracks the need to update
-    // style->font() with this bool.
-    bool m_fontDirty;
+    enum class IsSetFlag {

[rune, 2015/02/03 12:25:40]

How about something more descriptive like DescriptorFlag?

[andersr, 2015/02/03 15:35:08]

Do you mean DescriptionFlag?

+        Weight,
+        Size,
+        Stretch,
+        Family,
+        FeatureSettings,
+        Script,
+        Style,
+        Variant,
+        VariantLigatures,
+        TextRendering,
+        Kerning,
+        FontSmoothing,
+
+        EffectiveZoom,
+        TextOrientation,
+        WritingMode
+    };
+
+    void set(IsSetFlag flag) { m_flags |= (1 << unsigned(flag)); }
+    bool isSet(IsSetFlag flag) const { return m_flags & (1 << unsigned(flag)); }
+
+    unsigned m_flags;
 };
 
 }
 
 #endif