Relayout RenderObjects with viewport-percentage CSS properties when viewport size changes

Source/core/rendering/style/RenderStyle.h

Index: Source/core/rendering/style/RenderStyle.h
diff --git a/Source/core/rendering/style/RenderStyle.h b/Source/core/rendering/style/RenderStyle.h
index 843774d22134090d0ff993aa7fd8b8b6cd65a9ed..a3cac9c9b7368809202886651b61a97b0bb32338 100644
--- a/Source/core/rendering/style/RenderStyle.h
+++ b/Source/core/rendering/style/RenderStyle.h
@@ -77,8 +77,12 @@
 template<typename T, typename U> inline bool compareEqual(const T& t, const U& u) { return t == static_cast<T>(u); }
 
 #define SET_VAR(group, variable, value) \
-    if (!compareEqual(group->variable, value)) \
-        group.access()->variable = value
+    do { \
+        if (!compareEqual(group->variable, value)) { \
+            group.access()->variable = value; \
+            updateMayHaveViewportPercentage(value); \

[leviw_travelin_and_unemployed, 2013/10/25 20:30:35]

I'm a little worried that this could be expensive, but I don't see a better way
to do it.

+        } \
+    } while (0)
 
 #define SET_BORDERVALUE_COLOR(group, variable, value) \
     if (!compareEqual(group->variable.color(), value)) \
@@ -122,6 +126,24 @@ class RenderStyle: public RefCounted<RenderStyle> {
     friend class CachedUAStyle; // Saves Border/Background information for later comparison.
 protected:
 
+    // Called from SET_VAR macro and setters with Length* arguments not using SET_VAR.
+    void updateMayHaveViewportPercentage(Length t)
+    {
+        if (t.isViewportPercentage())
+            inherited_flags.m_mayHaveViewportPercentageProperty = true;
+    }
+    void updateMayHaveViewportPercentage(LengthSize t)
+    {
+        if (t.width().isViewportPercentage() || t.height().isViewportPercentage())
+            inherited_flags.m_mayHaveViewportPercentageProperty = true;
+    }
+    void updateMayHaveViewportPercentage(LengthBox t)
+    {
+        if (t.top().isViewportPercentage() || t.left().isViewportPercentage() || t.right().isViewportPercentage() || t.bottom().isViewportPercentage())
+            inherited_flags.m_mayHaveViewportPercentageProperty = true;
+    }
+    template <typename T> void updateMayHaveViewportPercentage(T) { }
+
     // non-inherited attributes
     DataRef<StyleBoxData> m_box;
     DataRef<StyleVisualData> visual;
@@ -161,7 +183,8 @@ protected:
                 && (m_printColorAdjust == other.m_printColorAdjust)
                 && (_pointerEvents == other._pointerEvents)
                 && (_insideLink == other._insideLink)
-                && (m_writingMode == other.m_writingMode);
+                && (m_writingMode == other.m_writingMode)
+                && (m_mayHaveViewportPercentageProperty == other.m_mayHaveViewportPercentageProperty);
         }
 
         bool operator!=(const InheritedFlags& other) const { return !(*this == other); }
@@ -191,6 +214,13 @@ protected:
         // CSS Text Layout Module Level 3: Vertical writing support
         unsigned m_writingMode : 2; // WritingMode
         // 45 bits
+
+        // Not a CSS property. It's set to true when any property is set to a viewport-percentage length value.
+        // As a performance trade-off, it's not strictly accurate. It may be still true when there is no longer
+        // viewport-percentage properties. It's inherited to make sure it's set whenever there is possibility
+        // of viewport-percentage properties.
+        unsigned m_mayHaveViewportPercentageProperty : 1; // bool
+        // 46 bits
     } inherited_flags;
 
 // don't inherit
@@ -291,6 +321,7 @@ protected:
         inherited_flags._pointerEvents = initialPointerEvents();
         inherited_flags._insideLink = NotInsideLink;
         inherited_flags.m_writingMode = initialWritingMode();
+        inherited_flags.m_mayHaveViewportPercentageProperty = false;
 
         noninherited_flags._effectiveDisplay = noninherited_flags._originalDisplay = initialDisplay();
         noninherited_flags._overflowX = initialOverflowX();
@@ -416,6 +447,8 @@ public:
     void setHasPseudoStyle(PseudoId pseudo);
     bool hasUniquePseudoStyle() const;
 
+    bool mayHaveViewportPercentageProperty() const { return inherited_flags.m_mayHaveViewportPercentageProperty; }
+
     // attribute getter methods
 
     EDisplay display() const { return static_cast<EDisplay>(noninherited_flags._effectiveDisplay); }
@@ -1043,7 +1076,13 @@ public:
     void setClipRight(Length v) { SET_VAR(visual, clip.m_right, v); }
     void setClipTop(Length v) { SET_VAR(visual, clip.m_top, v); }
     void setClipBottom(Length v) { SET_VAR(visual, clip.m_bottom, v); }
-    void setClip(Length top, Length right, Length bottom, Length left);
+    void setClip(Length top, Length right, Length bottom, Length left)
+    {
+        setClipTop(top);
+        setClipRight(right);
+        setClipBottom(bottom);
+        setClipLeft(left);

[esprehn, 2013/10/25 22:25:51]

Can you put these at the bottom of the file (and the ones above too) since
they're not just one line. We don't usually put longer ones inside the class
def.

+    }
     void setClip(LengthBox box) { SET_VAR(visual, clip, box); }
 
     void setUnicodeBidi(EUnicodeBidi b) { noninherited_flags._unicodeBidi = b; }
@@ -1117,6 +1156,7 @@ public:
     void setMaskBoxImageSlices(LengthBox slices)
     {
         rareNonInheritedData.access()->m_maskBoxImage.setImageSlices(slices);
+        updateMayHaveViewportPercentage(slices);
     }
     void setMaskBoxImageSlicesFill(bool fill)
     {
@@ -1125,10 +1165,12 @@ public:
     void setMaskBoxImageWidth(LengthBox slices)
     {
         rareNonInheritedData.access()->m_maskBoxImage.setBorderSlices(slices);
+        updateMayHaveViewportPercentage(slices);
     }
     void setMaskBoxImageOutset(LengthBox outset)
     {
         rareNonInheritedData.access()->m_maskBoxImage.setOutset(outset);
+        updateMayHaveViewportPercentage(outset);
     }
     void setMaskXPosition(Length length) { SET_VAR(rareNonInheritedData, m_mask.m_xPosition, length); }
     void setMaskYPosition(Length length) { SET_VAR(rareNonInheritedData, m_mask.m_yPosition, length); }