Move viewport unit resolution to style recalc time

Source/core/css/CSSToLengthConversionData.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 19 matching lines @@
 
 #ifndef CSSToLengthConversionData_h
 #define CSSToLengthConversionData_h
 
 #include "wtf/Assertions.h"
 #include "wtf/Noncopyable.h"
 
 namespace WebCore {
 
 class RenderStyle;
+class RenderView;
 
 class CSSToLengthConversionData {
 public:
-    CSSToLengthConversionData(const RenderStyle* style, const RenderStyle* rootStyle, float zoom, bool computingFontSize = false)
+    CSSToLengthConversionData(const RenderStyle* style, const RenderStyle* rootStyle, const RenderView* renderView, float zoom, bool computingFontSize = false)
         : m_style(style)
         , m_rootStyle(rootStyle)
+        , m_renderView(renderView)
         , m_zoom(zoom)
         , m_useEffectiveZoom(false)
         , m_computingFontSize(computingFontSize)
     {
         ASSERT(zoom > 0);
     }
-    CSSToLengthConversionData(const RenderStyle* style, const RenderStyle* rootStyle, bool computingFontSize = false)
+    CSSToLengthConversionData(const RenderStyle* style, const RenderStyle* rootStyle, const RenderView* renderView, bool computingFontSize = false)
         : m_style(style)
         , m_rootStyle(rootStyle)
+        , m_renderView(renderView)
         , m_useEffectiveZoom(true)
         , m_computingFontSize(computingFontSize)
     {
     }
     const RenderStyle& style() const { return *m_style; }
     const RenderStyle& rootStyle() const { return *m_rootStyle; }
     float zoom() const;
     bool computingFontSize() const { return m_computingFontSize; }
 
+    // Accessing these marks the style as having viewport units

[johnme, 2013/12/18 12:04:15]

Do any other accessors mutate the object like this? Is there a cleaner
alternative?

[Timothy Loh, 2013/12/23 06:28:16]

I could move marking the style out into the conversion code that uses these in
CSSPrimitiveValue::computeLengthDouble. It would probably end up with a function
here markStyleAsHavingViewportUnits (since I'd rather this class stop returning
styles and just return pixel values for ems/exs/rems), and then this wouldn't be
a whole lot different to what's going on now?

+    double viewportWidthPercent() const;
+    double viewportHeightPercent() const;
+    double viewportMinPercent() const;
+    double viewportMaxPercent() const;
+
     void setStyle(const RenderStyle* style) { m_style = style; }
     void setRootStyle(const RenderStyle* rootStyle) { m_rootStyle = rootStyle; }
 
     CSSToLengthConversionData copyWithAdjustedZoom(float newZoom) const
     {
-        return CSSToLengthConversionData(m_style, m_rootStyle, newZoom, m_computingFontSize);
+        return CSSToLengthConversionData(m_style, m_rootStyle, m_renderView, newZoom, m_computingFontSize);
     }
 
 private:
     const RenderStyle* m_style;
     const RenderStyle* m_rootStyle;
+    const RenderView* m_renderView;
     float m_zoom;
     bool m_useEffectiveZoom;
     bool m_computingFontSize;
 };
 
 } // namespace WebCore
 
 #endif