Bug 655877 - Part 21: Avoid assertions when nsStyleContext::GetVisitedDependentColor is called for an SVG paint property. r=dbaron

layout/style/nsStyleContext.cpp

@@ -18,11 +18,14 @@
 #include "nsStyleContext.h"
 #include "prlog.h"
 #include "nsStyleAnimation.h"
+#include "mozilla/Util.h"
 
 #ifdef DEBUG
 // #define NOISY_DEBUG
 #endif
 
+using namespace mozilla;
+
 //----------------------------------------------------------------------
 
 
@@ -699,19 +702,38 @@ NS_NewStyleContext(nsStyleContext* aParentContext,
   return context;
 }
 
-static nscolor ExtractColor(nsCSSProperty aProperty,
-                            nsStyleContext *aStyleContext)
+static inline void
+ExtractAnimationValue(nsCSSProperty aProperty,
+                      nsStyleContext* aStyleContext,
+                      nsStyleAnimation::Value& aResult)
 {
-  nsStyleAnimation::Value val;
-#ifdef DEBUG
-  bool success =
-#endif
-    nsStyleAnimation::ExtractComputedValue(aProperty, aStyleContext, val);
+  DebugOnly<bool> success =
+    nsStyleAnimation::ExtractComputedValue(aProperty, aStyleContext, aResult);
   NS_ABORT_IF_FALSE(success,
                     "aProperty must be extractable by nsStyleAnimation");
+}
+
+static nscolor
+ExtractColor(nsCSSProperty aProperty,
+             nsStyleContext *aStyleContext)
+{
+  nsStyleAnimation::Value val;
+  ExtractAnimationValue(aProperty, aStyleContext, val);
   return val.GetColorValue();
 }
 
+static nscolor
+ExtractColorLenient(nsCSSProperty aProperty,
+                    nsStyleContext *aStyleContext)
+{
+  nsStyleAnimation::Value val;
+  ExtractAnimationValue(aProperty, aStyleContext, val);
+  if (val.GetUnit() == nsStyleAnimation::eUnit_Color) {
+    return val.GetColorValue();
+  }
+  return NS_RGBA(0, 0, 0, 0);
+}
+
 struct ColorIndexSet {
   PRUint8 colorIndex, alphaIndex;
 };
@@ -734,15 +756,20 @@ nsStyleContext::GetVisitedDependentColor(nsCSSProperty aProperty)
                aProperty == eCSSProperty_stroke,
                "we need to add to nsStyleContext::CalcStyleDifference");
 
+  bool isPaintProperty = aProperty == eCSSProperty_fill ||
+                         aProperty == eCSSProperty_stroke;
+
   nscolor colors[2];
-  colors[0] = ExtractColor(aProperty, this);
+  colors[0] = isPaintProperty ? ExtractColorLenient(aProperty, this)
+                              : ExtractColor(aProperty, this);
 
   nsStyleContext *visitedStyle = this->GetStyleIfVisited();
   if (!visitedStyle) {
     return colors[0];
   }
 
-  colors[1] = ExtractColor(aProperty, visitedStyle);
+  colors[1] = isPaintProperty ? ExtractColorLenient(aProperty, visitedStyle)
+                              : ExtractColor(aProperty, visitedStyle);
 
   return nsStyleContext::CombineVisitedColors(colors,
                                               this->RelevantLinkVisited());